one thing that you should do is make sure that your antennae is not near any wires on the back of your computer (if you are using a wirless nic) and also you might want to try to move around the access point to get the best signal. i moved my wap to the opposite side of a room that is tiny (moving it only about 8 feet) and the signal went from average to very good and my range is better. cables like your video cable seem to carry some bit of interference from what i can tell so try to mess with the antennae and your cables to provide low pings.
to test with pings, just use the "ping <ip address or host name> -t -l 1024" command in a command prompt window. that will continuously ping that ip address/host name (whichever you use) with a kilobyte of data (i have found that a larger packet size can indicate variances in pings easier, but your ping time will increase) and try to minimize the ping time. then simple do a normal ping and check the ping time.
this is what i did to get my wireless up and running smoothly. i kept getting dropped servers in multiplayer games and this fixed all of that.
good luck.