2003 1.6 Polo Classic

First of all, let me start by saying I'm a 62 year old woman, not an engine fundi.

I bought a beautiful, cherry red, used 2003 1.6 Polo Classic four weeks ago. Fuel injection, according to our son-in-law. It was running beautifully. Suddenly, when I started it last Friday, it made a slight clunking kind of noise. I live in Pretoria, South Africa, and it doesn't exactly get cold here. It started very easily but died as soon as I took my foot off the accelerator. I tried driving by using the handbrake and revving whenever I came to a stop street, speed hump or corner, but that proved to be too difficult, as the handbrake doesn't work very efficiently. My car simply will not idle at all.

About 2 weeks ago, the temperature light came on so, shortly afterwards, I pulled into a garage to have it checked. There was no water in the radiator. The pump jockey filled it up a few times, until the water stopped bubbling over and everything was fine until last Friday. I don't know if this is pertinent to the idling problem but can't imagine how.

Any ideas?