Wifi has 10mbps on Ps3, dial-up speeds on laptops??

Hey there, first post and I'm glad I found this forum as I've been driving myself nuts. Long story short, internet problems occoured and comcast came out and told me my router was bad. I went and bought one the same day, it worked but was very, very slow. Speed had dropped from 9-10 mbps to under 2.

After arguing with comcast, doing countless resets and being told I was experiencing packet loss (when hard-wired and through wi-fi) I Re-did everything, and hooked up my old desktop into the mix as well and these are the new results.

Desktop (hard wired) 10mbps
Laptop 1 (4 ft away) well under 1 mbps
Laptop 2 (3 rooms away) 2-3 mbps
Ps3 (4 ft away) - 10 mbps.

I'm pretty stumped as I can't see how everything is getting a different speed; especially as everything thats using wifi is slow except the PS3 which is getting direct connect speeds like the desktop. Unfortunately, I work from home on the internet and this is day #3 with issues, and comcast is telling us they won't come back out as its a router issue and not their problem.

I can work hardwired, but would really like to figure out if the new router is bad (what are the odds lol) or if it's some funky issue that comcast does need to address. Any help would be appreciated, I've given myself grey hairs over this.