Applying Canadian Visa and h1b stamping from Canada ?

Hi Friends,

Please help me. Here is my detail and questions.

I did my Masters from US and after that got OPT now I got H1B approval and my H1b is going to start from Oct 1, 2012. My job is direct in the company I mean no EVC model etc, I have to go to India in first week of November. My lawyer suggested me to go to Calgary for stamping in middle  of Oct. 2 Years ago i got Canadian visitor visa (now expired).  My questions are: 

What reason should i give to Canadian Embassy for visitor visa ? should i tell them about stamping and show them appointment letter of US Embassy or should i need sponsorship from Canada as previously i got from one of my friend ? 

When should i apply for Canadian visa before 1st Oct or after ? 

Calgary will be fine in my case ?

When i can go to Canada for stamping ? middle of Oct will be good ?

2 pay stubs are enough ?


Thanks in Advance.

Please help me.