Welcome to SUSE and Linux in general!
SLED 11 SP1 has been end of life for some time now. As you’ve only just installed it I advise you do a clean install of SLED 11 SP3. SP3 has built in support for more hardware. If the dongle doesn’t work with SP3 do post again. But there really is no point starting out with Linux using a version that is already unsupported.
The SLED 11 SP 3 iso can be obtained from
You only need DVD 1.
Personally I would look for a different way to network the machine. In the limited experience I’ve had with USB wifi dongles I’ve found that they just aren’t much good. They’re better than no network, but that’s really about all they have going for them. If the PC has Ethernet, and the info I found online suggests it does, consider getting some network over power line adapters boxes. I use these http://www.tp-link.com/en/products/details/?categoryid=1658&model=TL-PA511KIT but many makes and models are available. They’ll be much more reliable than a USB wireless and getting an Ethernet connection set up is trivial.