wireless router...

help..just got an insprion 1520 and also inspiron 530. i have wireless on both of them, also have two older laptops with usb adapter for wireless. what is a good router for a 3000 square foot house. we have  a D link starter kit but i have to be right in front of it to get a good connection with the laptop. we don't use the wireless with the desktop right now but the internet comes through the desktop then to the modem then the d link router,, am i doing something wrong here or is the router i have a piece of junk.. the pages load very slowly if i am far away (20 feet or more) from the router. we have a cable modem.. can't think of anything else.. please help me as its driving me nuts... !!