Unfortunately for that budget, you're pretty much stuck with only a camera body. The lens, especially one to use for wildlife or action shots, will likely cost twice or more what the camera does. You CAN get a camera body for $300-400ish, or a kit with a basic lens for under $500 - the Canon T1, Sony A290, Nikon D3100, Pentax KX all for example should still be findable for under $500, some under $400. All would be plenty capable of lovely daytime vacation shots, and could get great animal shots on the safari ride with the right lens reach. For a little more, you could step up to an even better camera that adds better low light ability or burst speed. But typically you'll want a lens that can reach out 200-300mm or so. That will add $200 to your prices for a very cheap, average quality zoom, or $700-1000 for a fast, higher quality zoom or prime. The stuff wildlife photographers use often go for three times that!
The basic kit lens you'll get with most DSLR bodies will be something like an 18-55mm. That's not enough reach for safari trucks, or shooting the animals on the walking trails. In a P&S, that's a 3x zoom. You do have much better resolution with a DSLR that can withstand much cropping and still give you a nice shot, but there's no substitute for a lens with some reach.
For a new DSLR, the Canon T1 or Sony A230 are probably the absolute bottom price - both are around $400 with the 18-55 kit lens, and for another $150 or so you could add a cheap 55-200mm or 70-200mm lens to get the reach. It'll be far short of what a DSLR can do for you with a good lens, but still faster and with better resolution and detail than you'll get from most P&S models, and still better low light ability.
