wireless issues

[jzr420]

So here's my problem:

I recently upgraded my router from a DLINK wireless G (DI-624) to a DLINK wireless N (DIR-628). I am still using my old DLINK USB G receiver (WUA-2340).
Upon upgrade, my connection speed (according to the windows network icon in the systray) went from 108Mbps to 54Mbps.
Now I'm thinking it has something to do with the fact that I'm still using my old G receiver, but am wondering if I am wrong.
I am prepared to upgrade my receiver to N as well, but was wondering on that note which is faster/more reliable? USB or PCI receivers?

not sure if it matters, but am running XP SP3.

Thanks alot guys, really appreciate any input you have.

 

[office politics]

the max speed set by 802.11g is 54 Mbps. however some routers have a special mode to allow speeds beyond this limit.

NetGear WGU624 Double 108 Mbps Wireless Firewall Router Router reviews - CNET Reviews

In addition to its hearty features, the Netgear WGU624 delivers fast performance in both the 2.4GHz and 5GHz bands. Set to Super G (108Mbps) mode, the router earned a 42.1Mbps score in both 802.11a and 802.11g modes in CNET Labs' tests.

i like usb adapters because i can easily remove and transfer the adapter to another computer. I've never had any issues the the performance of usb adapters. **knocks on wood**