Career advice: Post-doc away from my primary interest, or not I'm in a need of a career advice, and I can't really think up any better to ask than all of you.

There is a post-doc position within upgrading biofuel that I am almost certain to be offered. There is some catalysis involved, but it is somewhat away from my primary interests: Organic synthesis and polymers. Similar positions within these topics are scarce, but at my alma mater they would hire me immediately if they get the funds nescessary. 

What should I do? Accept being away from home ground for two years, working on getting funding for the Chemistry department, or sit tight and hope that a better fitting position comes along?

Cheers,

EDIT:
I would like to precise, that I am going to apply for funding for an industrial post-doc together with a company. They are highly interested in me, but lack the funding. The job would be way more aligned with synthesis and polymer chemistry - but I will have to take a calculated risk: There is a 60% success rate for the applications, but I'll have be without job (2 months) until we get a (hopefully) positive answer.
Is the post-doc really that career-determining?
The most important thing is to evaluate if you will be able to keep a steady output of papers during this post-doc, if you can't hit the ground running than you will lose time to get comfortable with new material, two years go by very quickly. Also you should consider if in your country a post-doc in a different place is valuable experience to get tenure. You are the only one that can decide.