[Solved] What to upgrade? (1-year old AMD system)

My rig is 1 year old and i want to give it a light upgrade for overall performance (gaming included). So i ask what should i upgrade:

-AMD Athlon II X3 440 @ X4 3,2mhz (Option A: Upgrade to a X4 955 BE for the L3 cache and more OC range and enabling my ram to go faster instead of 592mhz with my current OC)
-TX3 cooler
-ASRock M3A770DE
-8 GB Patriot (value) 1,5V 666mhz 9-9-9-24 @1,59V 592mhz 7-8-7-20-27 (can reach 720 mhz but after gaming for 1h it freezes, needs more volts but i have no heating spreader)
-2x Sapphire 1gb ddr5 HD 5670 (Crossfire) @ 840/1040
-Western Digital Green 750GB Sata II (Option B: Include a SSD for boot drive, like a 60GB corsair force series)
-Cooler Master Elite 500w

A new VGA is out of question cause over here reselling is quite difficult and a new one is beyond my budget right now. The new CPU or SSD are actualy on par in costs so they are my major choices.

Thanks all.

008 the board does support DDR3 and so are my memory sticks. I've oc'd the ram and downclocked them and the difference was not that noticeable at all to justify upgrading them to 1600 (i guess)... The SSD boot drive was the highest hope of performance gain but if it isnt that much good either i guess i'll let it be as aftcomet said it was already well balanced and maybe in the future upgrade the GPU.

Thx guys.

Best answer selected by brosso.