Wireless Network Lag


i have two WD TV lives within my home. one is wired to my home network via router. the other WD TV Live is wireless about 200 ft away. the problem is, the wireless connect to the network while watching avi movies, becomes choppy and is lagging, the connection was working fine for about a month - then stopped. could it be a signal problem or too many connect/devices connected at once? please help.

update: my WD TV Live is connect wirelessly using a MediaLink Wireless “N” USB adapter - pulling signal from my router which is a linksys E3000 connected to My World Book 2 network