heyo,
you need to convert your gpa to %, as that is the grading system ubc uses. so convert every single individual grade to a % (ie. A= 86%, A-= 80% etc...) and then take that average to determine your overall percentage. It should probably be close to 85% to make you competitive as OOP
UBC values EC's big time, but OOP is a different monster as there are a lot of you competing for just a few seats; so what I am saying is that grades are very important as an OOP applicant (I think up to 29 out of 288 seats are for OOP students). If you have any more questions feel free to ask.