cap exempt H1 to cap H1

[energy]

I am presently at a University setting with a cap-exempt H1 Visa (that started in 2010 and will expire in 2013). I am looking at the possibility of joining a non cap position in Oct 2011. I have to give 3 month notice to my present employment before leaving (will tell them in beginning of July 2011)

1. If my new employment was to apply for my H1 cap visa to start in Oct 2011 do I need to tell my present employer right now or can I wait till start of July?

2. If my cap H1 at the new employer gets approved in the next few months to start in Oct 2011, can I still work at my present job on my cap exempt H1 visa till start of Oct 2011?

3. Would I have to leave the country to get the visa stamped?

4. How long will the cap H1 application take to get approved?

Thank you.