If you bought is a couple years ago, have you updated the firmware anytime recently?
If not, I'd suggest giving that a try to begin with.
As to changing the router, what you paid for it isn't really relevant; that's a sunk cost. If replacing it is the only apparent route then the question is what would it cost for a new one in comparison to what the old one would fetch on ebay.
Actually we did update the firmware recently because after my boyfriend got his Xoom, it got 10 times worse. Both my iPad and his Xoom would just stop connecting to the internet. It would show the wireless signal and it would be connected, but everything would time out. Everything worked fine from my laptop connected to the wireless though. We would have to reboot the router and then everything would work fine for a few more hours before it would do it again. It was weird because this literally happened the day he brought the Xoom home and it seemed to only affect the tablets.
We updated the firmware on the router and it has gotten better. We haven't had the time out issue but I do still lose connection once in a while. It used to drop several times each time I use it and now it only drops once every few times I use it so it is a LOT better...
I know the price isn't really relevant but the reason it was so expensive is because it has some features he said we need..which means replacing it would be just as expensive. I don't know anything about routers so I have no idea why we need it. Before we moved in together, I was fine with my cheap wireless router.