There is no real best wireless for gaming. Now if you bought a wireless dongle that is very tiny or talks about being green and saving energy that could be your problem. You want a usb dongle with larger antenna which means physically larger or maybe external antenna.
If you have not already tried it try using a usb extension cable to see if you can place the dongle in a better location in your room.
In most cases the problem is your house or maybe your neighbors using wifi. A different nic card can not fix those problems.
Even the very best nic card is subject to random interference which will causes massive issues with a game.
Your best option likely is to look at poweline adapters, look at the av2 based ones that claim...