I've just looked up your board and it doesn't seem like that one will support AM3 chips so upgrading with your current board is pretty much out of the question.
That means you need a new board, CPU and RAM so you can upgrade to whatever you like/can afford.
An LGA1155 board would give you a lot of options and some future proofing. LGA1155 is the slot on the board, which determines CPU compatibility. All second generation Core processors are LGA1155, so right the way from lowly dual core i3s to the amazing i5 2500k and the overkill i7 2600k. My opinion would be to go for an i5 2500k on a P68 motherboard.
I couldn't recommend an AMD, cause I don't see the point in buying equipment which is already obsolete.
TL;DR Save up for an i5 2500k and a P68 motherboard
EDIT - Just seen some of the above posts, odd. A quick search suggested that it couldn't take an AM3 chip.