Problems with lag spikes

[british]

Wondering if anyone can help me figure this out;

Experiencing pretty bad spikes about 5 - 10 times a half, each lasting around 5 seconds. My ping shoots up to 4095 and my player is frozen.

I don't know if its to do with RAM or my internet.

I recently upgraded to win7 64bit but i'm still only using 1gig of ram. When DoD is open and connected and ram usage is 90~

I also moved my computer upstairs, so i am no longer hard wired to the internet, instead i'm using a USB WiFi adapter.

If anyone can direct me to maybe some sort of test i can run? Or if anyone else has had this problem by playing through USB WiFi

Or maybe does the internet just suck here in tempe?

Thank you.