Unfortunately, you will not be able to any DirectX 8 games or higher. The SiS Mirage 662 only supports up to DirectX 7.
See following review of a mobo with that chipset:http://www.bjorn3d.com/read.php?cID=1023&pageID=2914
The integrated Mirage 1 graphics is also a disappointment for SG-95. The Mirage 1 comes with only DirectX 7 support (that’s 1999 technology), which means that it won’t be Vista capable nor it is a good choice for even running any games, except maybe Solitaire.
You will need to buy a video card if you want to play Warcraft 3. If your motherboard has a PCI-e interface, then I would recommend a HD 5570 or HD 5670. Both do not use much power and should suffice for W3. Of course the more powerful HD 5670 is also a little more expensive. I think it's around $85 - $90 for the 512MB version.