A wireless networking quandary

Some friends of mine have a Netgear CG814WG ( http://www.netgear.com/Products/RoutersandGateways/WirelessGRouters/CG814WG.aspx?detail=Specifications ) and they aren't getting much range out of it. They need their network to stretch from one end of their house to the other; unfortunately they can't relocate the router to a more central location. I suggested using a booster antenna, but I don't know anything about them. I'm getting the sense that it might work just as well to pick up another wireless router and use it as a wireless access point, but I don't know anything about getting that working either. Curiously, Netgear's guide on improving range explicitly says that their routers are not designed for this purpose (not sure if that means it won't work right or if they just want you to spring for one of their more expensive access points). Finally, I can't even tell from the router's product page if it has the necessary SMA/TNC connector to hook up another antenna, if that's even the way I should be going with this.

Can anyone offer me a bit of advice on this matter?

Yeah actually. You don't want to use a router to do it. You MAY be able to, but you'd have to change what fundamentally makes a router a router(dhcp servers do not play well together) A range booster will work, but I have no idea how to set one up as I live in a tiny apartment and if anyone calls in trying to set one up I give them their ssid and key and punt them to netgear or whoever they bought the thing from.

tl;dr
Get a booster, know your wireless info, call the people who made the damn thing.