If the 2.48 version doesn't work (which you've stated) try getting the latest version (2.58) from Realtek themselves here
. Tick the box that you accept then click next, it's the top one, described as 'Vista, Windows7 Driver (32/64bits) Driver only (Executable file)'
. The download is to the right, click on GO on either Site 1, 2, or 3, doesn't matter, they're just downloadservers.