Will using my wireless g router as a modem for AE bottleneck the speed?

After receiving poor internet around the house using my talktalk wireless g router (built in modem) I've decided to upgrade to wireless n.

My question is if I buy an airport extreme base station and run a cable from an ethernet port out of the talktalk router into the uplink on the AE, would the g router bottleneck the wireless n speed of the AE?

Sorry if this is a stupid question and thank you in advance for any help!

If you are running a cable out to the Airport extreme you wouldn't really use the wireless g from the talktalk modem. Usually there is a way to turn off wireless if you aren't using it - on the router. Then just use the Airport Extreme as your wireless base station.

I thought the exact same thing when I originally thought about doing this, but apparently the router talktalk supplied me with is so bad it doesn't even have an independent wifi off switch - just an on off switch which after checking switches off the modem too, thank you nonetheless.