Any solutions?

I have a 1987 Dodge Raider aka Mitsubishi Pajero/Montero/Shogun/whatever the hell you want to call it. This weekend, I decided to put new coolant in. Since, it's old a piece of the radiator's neck chipped off. So the radiator cap isn't fully secure. Some of the fluid leaks out. Another problem I have is that the inside seems to be rusted since all the fluid is orange as it leaks out. Is there a way to fix that? My friends suggested that I get a new radiator, but I wouldn't know where to get one since it is an old model. Is there anywhere I can find one for my Raider? But I've been thinking about buying a car for about $1000 dollars since I can't afford a new one. Possibly the Mk1 GTI or Beetle. No where to be found though. What should I do? I'd like to hear your suggestions. Thanks!