I personally would not pay anything for that place because it is not likely to ever earn a profit, at least not enough to justify the expense. You have too much competition. Even if you divide it into two screens, that is not likely to add much more revenue. It will just make it possible to operate.
Fifteen miles isn't very far. I had a two screen theater about 25 miles from the nearest competition. I think an awful lot of my potential customers had no issue with making the drive to see what they wanted. You will not get all the best movies on the national release date... maybe some. So, they go elsewhere. Some customers may wait, but much revenue is lost to the competitors who will get everything on opening day.
The reason two screens is better, as you may know, is because you will be required to hold new releases two, three, or even four weeks in order to get them on the release date. With two screens you can have a different movie about 2/3 of the time, assuming you are stuck playing new releases 3 weeks a lot of the time. And not every movie is interesting to everyone. Some can't even draw flies in a small town. So you make a profit only part of the time, when you have a popular movie or two. The rest of the time, it will be lucky to break even, and may not even do that in slow times.
If the theater already has good industry standard digital projection and sound, that helps the value. But, you will have to make the place ADA compliant and put in a fire sprinkler system if you convert to two screens. That reduces how much you should pay. You will decrease your seating capacity when you divide the auditorium and add ADA compliance. Maybe you will end up with one screen seating 100 and the other 50 or some such similar scenario. It could be even lower numbers since you have to add new ADA compliant restrooms. Although, fewer seats won't kill you since most will be empty more often than not.
You will need to hire an architect, because it is a place of assembly. They don't work cheap either (mine cost $10,000). You will have to move/add restrooms, upgrade plumbing, change out wiring (old wiring will likely have to be replaced to bring it up to code), possibly change out HVAC systems (if they are old), pay for that sprinkler system (if you run the pipes exposed beneath the ceiling then it will cost 1/3 of the ones I had put in the attic because it's a different kind of system), and move/build new sound barrier walls. And, don't forget the booth may have to be moved or drastically modified in order to be able to put an image on the second screen (no you probably can't just hang another projector from a ceiling somewhere), and you will have to buy more digital projection and sound equipment as well as another screen. You may have to install more exit doors, etc.
Twinning a theater is no small task. And starting with one that small is extra challenging. I did something very similar, but I also took a huge loss when I sold to the next owners, who had to invest more to upgrade to digital equipment. While I operated, I essentially broke even, and that's because I didn't have big loan payments each month. I spent about $200,000 above the initial purchase price of the property to get it up and running. About $50,000 of that was for mostly used equipment (film, not digital) and seats, etc. I did a lot of the work myself and I acted as my own general contractor. You might avoid some of the expenses I had, such as needing a new façade and side wall that were falling apart, but you might have others I didn't, such as hiring a general contractor. So, if you can do it for less than $200,000, then you will have done better than me.
Now, how much do you think that theater is worth that was showing a small loss, and will require a big cash influx beyond the purchase price? I wouldn't do it for a market area of 10,000 people in competition with 36 screens 15 miles away, but you may be willing to do it as a labor of love for the community. Just be aware of what you are getting yourself into. But, if it's just a love for the community and a local theater, then why not just keep it as a single screen and book movies that have been out for about a month. You would be able to book them for only a week and get something new every week if so desired. It won't likely perform any better for you than the previous owners, but the investment will be so much lower that the probable loss will be easier to swallow. It will essentially be an expensive hobby that you can share with your family and friends.
There's also the possibility of converting it to a non-profit.