Interferences: nothing much you can do about this. Interferences can be any device operating within the same frequency as 802.11b/g, such as 2.4Ghz cordless phone, other wireless router, Bluetooth devices are known to jump across this frequency creating interferences, the microwave, and possibly many other things.
Security features: I also notice this model has many security features, that is possibly why it's over $120. Lower your security settings, check and see what wireless security setting may interrupt your communication such as WPA and MAC address authentication.
Channels: Change it to something else, you have from 1 to 11, try 1, then 6, then 11 or in between each.