my current cpu

and the mother board

My computer is HP a6560t, recently I am planing to doing an upgrade.
I am not sure if i can just upgrade the cpu without change the board. what is the best cpu today that can still use this board?
and what I can do with the old cpu after the upgrade? I am not sure people will want to buy second hand cpu off ebay.

and the mother board

My computer is HP a6560t, recently I am planing to doing an upgrade.
I am not sure if i can just upgrade the cpu without change the board. what is the best cpu today that can still use this board?
and what I can do with the old cpu after the upgrade? I am not sure people will want to buy second hand cpu off ebay.
