well mate you are experienced..I would suggest to think over your program selection...you said you are interested in improving your skills in computer engineering then why to go for Prj Mgmt? I would suggest you to search and find a Post graduate program related to your interest..Since you'll be investing 7lakhs+ on tution itself then make sure you get what you desire..you must be aware that where do you see yourself in future after completing either PG in comp engg or a PG in project management..obviously it has to be what you are interested in rather than what can get you to canada..
btw a diploma course is an entry level course so dont expect a lot..trust me even if you get a visa it will be useless to spend the money..as you are already a graduate engineer..and your highest qualification will still be BE after completing the diploma course...so dont expect huge increase in pay after completion.. its kindof going backwards isnt it? your visa for diploma will most probably be rejected..
regarding project management..its a good choice but depends on person to person..some may be technicaly gifted who know how to execute the work and some are good at getting the work done from others..
just sit down..relax..find out your interest and where you want to see yourself in future, chose a program accordingly, check course contents whether they suit your requirement..than you'll actually have a SOP and no one can stop you from studing and then having a bright future!