Hi Chahal
Q1) Can I study in Canada as I have 3 years gap?
GAP is not an Issue but you might give proper details to the CHC regarding your gap i mine experience letters,etc.
Q2) Should I go for Post-secondary OR Post-graduate studies?
Well this depends on you what degree you want to achieve or eligible for...
Q4) Should I choose SPP or Non-SPP?
In my opinion yes you should go for SPP as it has got fast process and less rejection ratio (98% Approval Ratio)
Q3) Can I apply for my spouse with my application? If yes, What is the procedure? (Spouse Qualification = Under Graduation in 2004, Currently working as Team Leader in software company.)
This decision is upto you..... you both are eligible