International Student now being offered a permanent job

Hi,

I am so worried and lost as to what my next step should be when HR asks me my work permit.

I am an International student and finished the course credits after which I was to gather work experience credits (6months) , I luckily got a practicum position back in Oct 2010 (upto April 2011) but now 3 months down the line my manager likes me and has already approved my permanent position, an offer letter will be presented to me shortly.
Now my work permit ends in August 2011, but by May 2011 I intend to apply for my Post Grad WP (probably 2-3 year duration), and then gather the 1 year experience and apply for PR under CEC.
But how do I explain this to the HR??? will it matter??? my current work term with the company is under a temp work permit, and if they offer me a permanent one starting April 2011, do I have to have a permanent work permit?? or will they allow me to work on a temporary WP and then wait till I get my PR? Huh

I am so scared, I have worked hard to prove myself into being an asset to the company, I also do not want to go through getting them to apply for my work permit - LMO and stuff....they might just drop me for somone else, then going through all this hassle.
Hoping somone understands my position.... Sad

thank you....appreciate your help.

Regards,

Aldrin