I have the same router. It seems to not like it when my parents pile clothes on top of it. It gets pretty hot after a few hours of being blanketed.
Make sure it's not sufficating. Other than that, try updating firmware.
But overall, I haven't had many problems with mine. If all else fails, get a needle and press the little reset switch and hold it down for a few seconds. After a while, the router should reboot. Then run network setup wizard on all the machines, and restart each of them.
You may want to also try restarting your cable modem as well. It might just be poor service, or a dieing cable modem. Next time the connection dies, check your cable modem and make sure you see a the data light on (not flashing), and the cable connection light on (not flashing). It can flicker, but usually when it flashes in a steady on off way, it usually means your having ISP problems.
Give your cable company a call and see what they can do. But they probably wont take any responsibility for troubleshooting your router/network.
Hope you figure it out. If you have any more questions, feel free to ask!