|I'm not aware of wireless routers supporting 802.11n, that do not support 802.11g.|
To be absolutely sure, simply take a look at the datasheet of the router, you'd like to buy.
There are listed all the supported wireless standards, like 802.11n, 802.11g, 802.11b a.s.o.
The original poster should always write the last response !!!
Let us know, if the problem is solved !!!