I took another job 2 weeks after , so guess i can only claim 2 weeks ?
You can try, there might be a 4 week minimum period without work before any payment, if you catch my drift. I can't remember as I specifically was dealing with what should have been a 12 week notice period. If it is worth your while re-read the documentation you have received from the liquidatators and then go to or you can probably even e-mail the CAB.
As you have probably realised you have zero chance of getting 12 weeks now, I am afraid.