As the others have said, it's tough. I was in your position 12 months ago and enrolled in a SCITT course. Your main options are GTP (paid but hitting the ground running), SCITT (School based but you pay) and PGCE (Uni based, you pay).
Biology doesn't command as much of a grant as the other sciences but can cover up to the course fees.
It's been the hardest year's work I've done to date (including writing up my PhD) and will continue to be hard for the foreseeable but, and it's a big but, definitely the most rewarding. I've got a job for next year [NQT] but there's no guarantee of employment at the end of it. Of course as long as Mr Gove keeps chasing people out of the job there will continue to be vacancies but that's an argument for another thread!
Good luck with your decision.
Edit: I'd also recommend getting in to school to see how things are run. For me it was a big shock going back into a school some 20 odd years after I'd last left!