Internet Disconnects And Is Slow

i did a clean install of windows 7 due to reg problems at the start of this year.before that the wifi went fine it did not disconnect of me and windows was not saying that it can find the network.so the problem is that when i am in my room it runs very slow at times and disconnects and windows says there is no wifi but if i move outside my door it finds it and connects i find this odd since windows says it a good connection almost full bars and speed running at 54(the top speed) and 48 it the connection speed and signal drop down low at times (but only in my room no where else) any ideas? [code]