Modem replacement- clueless

I want to buy a new modem to replace the one we got with our package three years ago. The internet frequently clocks out, the download and upload speeds are terrible, and I find the problems overall annoying. I found a modem/router/firewall/gateway on the egg, that has a download stream in the range I am looking for to optimize my internet package, however I know nothing about modems, routers, or any of that stuff at all...

So, is this a good deal? Will it do what I want it to do, and what may be some problems I may face if I buy this and try to install it myself (btw I have a wireless router too that I would still need to use).

http://www.newegg.com/Product/Prod [...] 6825115020