Wireless N and G, interferance when physically next to each other?

I've looked over the forums and google and have been unable to find a clear answer. Here is my situation. I have a 7.0mbps DSL modem/wireless G router in my kitchen. I currently connect my Laptop, XBOX 360 and desktop to the wireless network. I get great steady speed but it's G speed. Can I setup a wireless N1 router right next to the current router and use the N speeds for my desktop upstairs, while keeping my Xbox 360 and laptop connecting to the G network so they don't slow down the N network?

Will the networks interfere with each other since they are literally being broadcast next to each other?

Thanks.

setup netcard speed auto to 802.11 G mode,and make sure no one 802.11 a/b card in your wordgroup .there has rule,if there are different mode wrielesscard in wireless network,it will auto slow speed down to compatible .so .....