If you haven't got a multitool, I'd recommend this one http://www.wiggle.co.uk/topeak-hexus-ii-16-function-multi-tool/ . It includes a very good chain breaker. But before you break your chain, try oiling it. Use the @mickle method (do we still call it that?) http://www.cyclorama.net/blog/advice/51/ You just need some oil, and an bit of an old t-shirt. If it's still moving well, the rust may be just cosmetic, and this should clean it up. Generally I'd expect a chain to last longer than a tube.
Edit: Don't use the tyre levers on the multitool. Apparently they break easily, and you need them for other purposes. I like Park Tools levers http://www.wiggle.co.uk/park-tool-tl1c-tyre-levers/
Managed to change my tube without any problems. I've actually also borrowed my mate's GT40 and sprayed the chain while giving it a wipe, most of the rust's effects seem to have disappeared, you're right jefmcg! the rust is just cosmetic and my ride feels new again. i'll probably change my chain when my it is more worn out.
Will keep this thread in mind when I do actually change it.
Thanks for everything guys! Appreciate the help