switching from tier 2 ICT long term to tier to ICT dependant

[snigdha]

Hi,

I am currently on ICT tier 2 long term visa. I have submitted my resignation though the last working date is still not decided. I have few queries

1. Can I switch to dependant visa from within uk. My husband is working on ICT tier 2 long term visa through a different organisation. Or I need to go back to india to process my visa

2. Do I need to apply for dependant visa before my last working date or can I do I after it.

3. Is relieving letter from current employer required while applying for dependant visa. If I legally I am required to apply before my last working date, do I need to submit any documents to prove that I have resigned.

4. Is there a duration for which I can stay legally in uk after my last working date.

I have gone through UKBA site but unable to find any information.

Regards
Snigdha