Info needed about switching from JSA to dole.

In December I had my JSA cut and went to a meeting 6 weeks ago about getting back on JSA while still working part time. I was told that I would have to be means tested and it could take anything up to four months, but to keep handing in my slips every week as my payments would be back dated. Last week I was let go from work and went into the dole office to make them aware and hand in my p45. Just wondering does anyone know how long will take to get my back dated payments and also can I start signing on straight away and getting my dole as I currently have no source of income. I was given a temp card for going to the post office but wasn't told when I can begin signing on, only that I would receive information in the post, but havent heard anything or received any information so far. Thanks for any help you can give me.