You don't necessarily need a degree from a University in the Same field. A Diploma will suffice (take the test on the CIC Website) to assess your points. It all depends on whether you achieve the 67Points benchmark.However, you do need to fulfill the NOC 0213 requirements as mentioned in the NOC classification.
CUT is right by saying that in IT, your Qualification does not need to match your profession.
Professional Certificates together with a degree(in any field), IT Training, Employment Contract(s), Pay stubs, References etc. would be great to prove your experience. Certifications ( Microsoft, Comptia (especially in the US and Canada), CISCO, NOVELL, LP, ITIL etc. are a plus point as I have gathered from the researches done. Being a Member of a professional body like the CITPS, BCS etc is also seen positively.