Replacement AM2/AM2+ CPU

Hey guys, I busted up my old cpu and i need a quick fix. I really don't want to get into the details, it was very stupid but bottom line, i'm in need a of a new CPU and possibly a motherboard (but hopefully not).

Off the bat, is it bad and/or easily fixable if the lever that locks your CPU down in your mother is broken? I may have broken that, but it's tough to tell, it feels flimsy, but I've only ever locked it when there has been a CPU inside already so I'm not sure (what is an easy way to check). If i also need then don't bother i'll have a lot to rethink. I use it mostly for gaming and a bit of video encoding.

Here is my system:
Gigabyte ga-ma78gm-us2h motherboard (possibly broken)
2 x 2GB Corsair XMS2 DDR2 800 RAM
9600GT (have a 9800gtx+ i may put in when i get something new in a different system)
500GB Hitachi deskstar HDD
OCZ 700W Modular PSU
Windows XP Pro SP3

My old CPU was an Athlon 7750 Black Edition that I had clocked at 3.2GHz.
I really wasn't planning on having to buy a new processor now, so budget is tight, and since the AM2 and + sockets are old, I'm struggling to find many decent CPUs. What is the best CPU I can get for ~100$ canadian, with comparable or better performance than my old one?
I plan on doing a fair bit of overclocking as I have an OCZ Gladiator heatsink with nothing to cool.

http://www.newegg.ca/Product/Produ [...] k=x3%20435

45nm, vastly overclockable, ull make the right choice

Phenom II X2 545 Callisto 3.0GHz AM3 80w

because it uses ddr2 ram, whereas am3 is for ddr3 only.