If you feel it's the repeater look for new firmware for that. But there are a lot of routers with buggy code. My rather new router arrived with a bug/defect and it took a few months before they fixed it. I would have returned it but it was not as bad as your issue.
I recently took my old Linksys wrt54g router and installed the ddrt software and now I 'm using it as a repeater. The issue i'm having is that every 24 hours I have to reset the repeater although it is saying it's connected, I can't connect. I've been tracking it for a few days to see if was a pattern and it is at the same time everyday. Is there something in the admin that can be changed to fix this? Any suggestions would be great.