Well it does support the Athlon X2 7750 and chances are it is using a BIOS revision of the same or later that supports that cpu. later revisions of firmware for that board does support nearly all of the K10 45nm desktop skus.
AMD is more flexible in the way of fitting newer processors in older motherboards. for example the Asus M2N SLI Deluxe AM2 motherboard does not natively ,or out of box, support any 45nm processors but later BIOS update will allow a K10 Athlon x2 or Athlon II to work , there is a number of other AM2 boards that fit this scenario and they are pretty cheap now. If i were you i wou;d just get an AM3 or AM3+ socket motherboard instead an AM2 or AM2/AM2+ socket just for compatibility reasons. Like a GA-990FXA-UD3 which is quite popular, but your more likely to see something with a 760G chipset or even 970 chipset for much cheaper.