Look for sources of wireless interference.
Cordless phones, Microwaves, other wireless networks, Power lines, etc can all slow wireless to a crawl. Also distance and metal between you and the base station. Old houses with plaster lathe walls are the death of wireless.
In an apartment you may also be getting interference from neighbors devices. I had a problem every time I heard a neighbors phone ring.
Log into your router and experiment with changing the channel. You may have to try several times to get one that works.
You can do this by typing 192.168.1.1 into the browser if you have a Netgear. The number is different for other brands.
If that fails try a 5Mhz router or a dual band router that can operate in both 5 and 2.4 Ghz range.