So if you restart the DSL modem only, the problem goes away temporarily? And if you restart only the router, the problem goes away again, temporarily? Or when you reset the DSL modem, were you resetting the router as well? I ask this because if resetting each by itself will temporarily solve it, then I don't think you can blame the router quite yet.
For example, while I was with AT&T DSL I had an issue with my Speedstream 5100 modem where often(at least once a day) it would simply stop passing anything through. I could still reach both the router and the modem, but couldn't get anything past the modem to the Internet. If I reset the DSL modem, it would work again. If I reset the router, it would also work again. I eventually found(best I can tell), the issue is with NAT on the modem. I never ran into this problem until I attempted to run more than one computer on the network. When using PPoE on the modem, the router before it will nat everything to it's own IP of course, but then the modem still must nat everything again. I imagine the modem's nat session table was filling(or some other bug existed); resetting the modem of course cleared it, while resetting the router seemed to clear it as well(my guess is the modem's lan port briefly dropping was triggering a reset of the session table). Simply switching to use PPPoE on the router rather than the modem, fixed the problem. I don't have Fusion(switched my DSL to Sonic a few weeks ago, cause of AT&T's caps), so don't know anything about your modem nor your network config, of course; I simply mean to say, you might want to double check before you buy a new router.