As a 13 year old budding gamer , I am wondering the best gaming/workstation build for around $800 / £500, (Live in Scotland) however I do not need a CPU cooler or case, but want a GTX 660 or above. I am thinking about the GeIL Dragon RAM and i5 3750 (not K) but might opt for an ebay i7. I also have a 380W Cooler Master PSU, but am not sure about its usage.
If anyone could help I would be greatly appreciated.
Slightly over budget. You could drop to the slightly lower performance i5-3470, it could be considered better value.
I have gone with Corsair RAM, as your suggested RAM is 1.6v, above the recommended max of 1.5v
380w isn't really adequate. Even if it was an actual 380w (by no means guaranteed, with CoolerMaster, I'm afraid), it would be working too hard, for reliability, especially if you wish to overclock GPU. 450w is about minimum, I could recommend. The one chosen, is very good quality, at sensible price.
You didn't specify form factor of existing case. I have therefore selected mATX motherboard (will still fit ATX case). If case is ATX, you could use ATX mobo, which would give more scope for expansion, in future, for only slightly higher cost.