Cable Modem Router

It sounds like an issue with the wireless and not with the actual internet, you probably have a lot of interference from neighbors who are using the same frequencies you are using and drowning you out. If you have an ethernet cable you should try plugging that into the router and seeing if the connection is still unstable to confirm. If that is the problem then the next thing to try is changing the wireless channel, 1 6 and 11 are the non-overlapping ones and one of those could be less crowded than the one you are currently on. If the wireless channel doesn't help then you need to connect to your router some other way, either you could rely on ethernet cable, which is the cheapest and most reliable but comes with the cost of running cable or you could buy a 5Ghz router (and a 5Ghz receiver for your laptop if it doesn't have it built in) but it is possible (but much much less likely) that the 5Ghz band is also crowded, also the 5Ghz band has less penetration through walls so if the walls are thick you might have an issue.