We have a Buffalo AirStation WHR-HP-G300N as the main router. We also have an Asus RT-N53 router located one floor higher. I've set the Asus router to act as a repeater for the Buffalo. There is a problem with it though. My table isn't taking any benefit due to the repeater router. My phone gets a great signal though. Well, it gets it notwithstanding the extra router.
The Buffalo router is running DD-WRT and Asus is running on stock firmware.
The Asus router doesn't seem to be able to act only as a repeater device since it has to broadcast it's own SSID for both 2.4 GHz and 5 GHz frequencies. By the way, the tablet gets an excellent signal when connected to the SSID broadcasted by the Asus router.