Dead Polo after driving through floods

Hi,

I had to get to work a couple of weeks ago and drove my T Reg 1.4 Polo through a couple of fairly deep floods. The car was fine at the time and I got to work no problem.

When I left work however the car was really labouring, I had to keep the revs high to pull away, no grunt at all almost as though it had lost a couple of cylinders. I thought it was probably water that had got into the dist cap, so I've let it dry out over the last couple of weeks and tried it again today.

The car is completely dead, no lights when you turn the ignition. So battery problem. Tried to jump start off my diesel astra, the lights came on on the dash when I turned the key, turned over very very sluggishly twice then nothing and lights went off again. I'm thinking I burnt out the cables? (Tried repositioning etc and still nothing).

So - what are my options? Do I go out on a limb and just buy a new battery? Do I buy a trickle charger and try and get some life back into it - it's only a year old (bearing in mind there's nothing at all at the moment). Or is there something else at fault here - a short circuit which has caused it to drain in the first place - and it needs to be taken to a garage.

I'm limited on what I can do tool wise.

Thanks in advance.