Maximum PC

Hi I've got some questions and please let me know if I need to do more homework or tests, I have Comcast cable internet and its 30mb down not sure on the up, I have a wireless router setup my room mate is plugged directly into it. The router were using is a netgear WGR614v10 its an older model but had good reviews. The problem is when I do a speedtest from speedtest.net I rarely if ever even get up to 10mb down and I like to stream movies on my xbox from zune and it struggles as far as quality goes I think it should be able to stream in full 1080 no problem. So im fairly tech savy and im curious if a router would make a difference or maybe a different cable modem then the one Comcast provided? Im not real familiar with dd-wrt but it seems to be the way to go? And if so should I maybe simplify the process and get one from https://www.flashrouters.com/ Thanks for taking the time to read. Any help would be much appreciated.

It's a wireless G router. You are hitting pretty good speeds for Wireless G, but if you want faster, upgrade to Wireless N.

I don't know what router to recommend, but I've had no problems with my WNR200v2 upgraded to DDWRT.

DDWRT gives you more control over your network, but takes more work to set up.

I've done some tests and here's what I've come up with, when I plug the cable modem directly into my laptop I get 35mb from speedtest then I unplugged it and kept my laptop right next to it and a 2nd test yielded 21mb then I put my laptop where I usually have it which isn't all the far roughly 10 to 12 feet in the next bedroom and it drops to 5 to 8 mb?? That seems odd? Switching to a wireless N would solve the problem you think?

It will.
Connected to the router, you are getting your max speed. That's because Ethernet is faster than wifi.
Right next to the router, signal strength is perfect, so you get high speeds.
In the next room, you get (and will still get) slower speeds, because of the interference.
Wires or building materials are making that wall shield your laptop from the router, slowing things down and degrading the link. You will still get slower speeds in the next room, but hopefully, they will be slightly faster than before. That said, 7-8Mbps is pretty fast -- I'm on a 1.5Mbps downlink.
My solution for fixing the problem for free: Go into the room with the router whenever you need to download anything big. 7-8Mbps is plenty fast for web surfing, and at those speeds, you can download a full 600mb CD (I'm thinking a Linux distro, not piracy) in 15-20 minutes.