Should I try the same model or a differnt model??
Get a different router altogether if you can return it for a full refund. If you can afford it, buy a Netgear WNDR3700 or an Apple Airport Extreme Base Station off craigslist. The WNDR3700 is the type of router that you need only buy once every 5 years and has great wireless performance and stability, but it is Atheros based so it won't support DD-WRT, but perhaps OpenWRT soon.
http://www.smallnetbuilder.com/content/view/30925/96/
If you have money and live in a populated area like and apartment, definitely get something with 5Ghz 11n.