The two chipsets you have is Broadcom for the Linksys and Atheros for the Belkin, mixing chipset vendors for WDS bridging (the technical name of what your asking for) is not well tested and typically doesn't work very well with links being dropped and lots of wireless troubleshooting work required.
That said, there are two ways to increase your speed/latency as I see it, and 11n is not a requirement in either one.
The first one is to get a 802.11a router or access point, and get a Wireless 11a adapter like this one
. If you pair it with a gaming 11a router, you will get LIKELY (not guaranteed) get better performance since fewer people use the 11a's 5Ghz (vs. 2.4Ghz for 11b, 11g, 11n, bluetooth, and microwave ovens). This will net you 54-108Mbps of raw dataspeeds, which translates into 20-45Mbps of real data (wi-fi uses a lot of overhead to handle the wireless connections and error correction).
The second option is to use a powerline ethernet
product like the Linksys PLK200
. What that will net you is 100+ Mbps of raw throughput, and 60-80Mbps of real data. You will also get lower latency (read: lower ping times) for games and a better network for streaming audio/video from pcs to your ps3. And yes, you are sending data over your home's powerlines to transmit the data.
The 11a solution will cost you some money, but you may find bargains as 11a isn't as popular and you may find stuff on ebay and craigslist for cheap. The Powerline ethernet solution will run you ~150 for a set of new powerline ethernet adapters, but maybe cheaper since they have been out for a few months. There are some newer adapters from other manufacturers that say 200Mbps, but I think this is overkill since most routers have 100Mbps ethernet ports anyways.
In case anyone wants to point it out, yes your home internet connection is the bottleneck, at 500kbps to 6Mbps typically, but for those streaming video or gaming online, the extra bandwidth can offer lower ping times for that extra nano-second advantage.