It's hard to help you without knowing the address so we can look at it ourselves. With that said, feel free to give me a call or email me and I'll put you touch with a Realtor I know who works the area you're talking about. I know she can help you determine the answer! Good luck!
They will do all the work on your behalf, they have the knowledge of the current market conditions and access to resources to provide you with the best information and advice. Best of all their service's are free to you.
Email me at Rm2081@gmail.com or visit my website at http://www.RealEstateByMaier.com. and I will be glad to provide you with more information.
None are as engaged as I am on Trulia, but run through the list and see if one of them can help you.
Making it unlikely that you could do a CMA or an appraisal.
It becomes a matter of what it is worth to YOU, and what the Seller will accept:
I would be ready with a generous down payment, (or an all cash offer), because the bank will want some good comp's to do the appraisal, and you'll be between a rock and a hard place.
Have your Realtor contact the Seller or his Agent; divorce yourself from the proceedings!
Good luck and may God bless