I'm in a bit of trouble, i need a better CPU then the dual core i currently have, but I'm not very hardware savvy. I need some help with finding a relatively cheap CPU that is still an improvement over the one i have, I'm a student so i don't have too much in the way of money but I'd need at least a quad core IF my motherboard is even compatible with that.

My current Hardware:

M.Board: Fujitsu Siemens MS-7293
Ram: 4 GB DDR2 (Passmark only recognizes 3 GB of it tho)
CPU: Intel Pentium D CPU 3.00GHz 2.99GHz
GPU: AMD Radeon HD 6700 Series