welcome to the forums. Its usually helpful to include as much information as possible when looking for assistance here, especially when you have wireless issues. giving some more information on what devices you use, the physical locations of the router and whatever device you use to connect and any troubleshooting steps youve already taken is a good start.
Heres a couple of thoughts...
possible issues can be signal interference from other wireless access points: try changing wireless channels in your router to 1, 6 or 11
physical interference is also possible: if you can get signal near the router but not in another room, walls (and whats in them) among other physical objects may be causing the problem