aztecaa

I have a long range antennae with RTL8187. I always connect to a certain wep for the past year and all of a sudden it won't stay connected. I see it in my available networks and also have it saved in profile. I noticed that most of my networks drop down to 1 mbps and are not the same as they were last year. What is causing this and can i add or change something in order to remedy this issue? Thanks