Let me start by saying that no one knows the recommended system requirements for DCS A-10C. I typically use the beta testers rigs as a benchmark to have a vauge idea of what to expect; however here is my recommendation that wouldn't break the bank.
My recommendation:
CPU:AMD Phenom II X6 1055T Thuban 2.8GHz
Motherboard: MSI 785GT-E63 AM3/AM2+/AM2 AMD 785G HDMI ATX AMD Motherboard
Graphics Card: ASUS ENGTX460 DirectCU TOP/2DI/768MD5 GeForce GTX 460
Memory: Kingston HyperX T1 Series 4GB (2 x 2GB)
OS: Windows 7 x64
You can use your imagaination on the optical drive, the case, the power supply (you shouldn't need anything above 700 watts for the above) and the HDD. And I didn't list a sound card because you can pretty much get away with an onboard sound card nowadays.
P.S.
I believe it is against the forum rules to request help in exchange for rep.