Wireless internet is always going to be somewhat slow and relatively unstable, even with a modern top end router.
If possible, use an ethernet cable for optimal stability and speed. A compromise that I use is Powerlines. It is as stable as ethernet and its speed is somewhere in between of wireless and traditional ethernet cable. Really nice sets can be picked up for as little as $80, even less if you are fine with less well known brands (just make sure you pick a recent 200Mb/s model, as they are better encrypted and a lot faster)
Routers are catching up or just as good as ethernet when it comes stability, it really all depends on the router (quality) and your base connection. These are a few good routers that I would recommend.(Listed below: Highest price to lowest) Also I would say 15 Mbps for me but thats high speed.
D-Link Xtreme Wireless N Router (DIR-825)
Linksys Wireless N Router (WRT310N-CA)
Linksys Home Wireless N Router (WRT160N)