Like SweetPoison said, FaceBook games use Flash. There is no Flash on the iPad, and other than Skyfire [which won't handle games or complicated Flash interfaces] there is no third party solution. Nor is there likely to be one anytime in the near future. Apple's policy excludes Flash on iOS devices.
Zynga and other FaceBook game developers have started to write apps for the iPad and iPhone. Cafe World doesn't appear to be one of them, but keep an eye out. It could show up. You could also go to the game developer's website or FaceBook page and ask if/when they intend to write an iPad version.
As for your speed. Restart your router. On the iPad, go to Settings / WiFi / and select the network. Tell the iPad to forget it. When the router is back up add the network again. This may help, may only help temporarily, or may not help at all, but it is the best I can do without suggesting a new router. Sorry.
There are several other threads on network problems with the iPad. Do a search and see if any of them have helpful suggestions.
Also, make sure you've got a strong signal. The iPad has a shorter range than most laptops or desktops. At least mine does. For some of us the last update seems to have effected the network speed and robustness. No fix for this but to wait for Apple to fix it, again.
What I did, finally, was set up a separate network for just my iPad. I had an old Airport Express laying around which the iPad seems to like better than my high end NetGear router.
