MBP battery dead

I've had my MBP for pretty much 2 years now and the battery has been getting pretty ropey recently - 15 mins charge, cutting out when it still displays about 50% etc (even though it's been calibrated relatively frequently). I then left it on with the top down (so sleeping) and being an idiot, completely forgot about it. Anyway, the battery has completely emptied and won't take any charge at all. When the laptop is on, the battery symbol just has a black cross over it, saying it doesn't recognise that there's one in there. I went on the apple support page and have looked over these:

http://support.apple.com/kb/HT1119?locale=en_GB

http://support.apple.com/kb/HT1411

So, I've left the battery to charge (for a day), re-seated it and re-set the SMC and it still isn't doing anything.

I'm guessing this is new battery time? They're £100 from apple, which is a lot - are there 3rd party ones that you lot know about that will be cheaper / better?

Thanks

// EDIT // Just realised this is in software. Have asked for it to be moved.

I got a genuine replacement for my Dell laptop from battery.co.uk (not sure if that qualifies as a competitor of not. mods?) Anyway, it worked out about £40 cheaper than buying from Dell themselves.

Cheers. They do have one and it is indeed cheaper.