Broadband router range

We just moved into a new home that is very spread out. My old linksys router could not get signal to my children's computers. Yesterday I went to best buy in orland park, il and spoke with a salesperson. He suggested the linksys wireless-n broadband router WRT160N which I purchased and intstalled. It is working properly but the signal still does not reach there rooms. I moved it to the center of the house and they get 2 bars but I do not have internet coming in at that point. Can I use a wireless G range expander with the wireless n router? I was on the linksys website and did not see a range extender for wireless n. If I can use a G range extender can I use multiple ones to push the signal further in the house?

Thank you,
Barbara Prunsky