As you have the index info you could order the certificate - there should be a cemetery where the burial took place listed on it - think it's $10 from the Municipal Archives.
If not call Calvary as they will check to see if there's a burial for an individual - all they require to do this is a name, month and year which you have. They'll give you the plot location if the burial took place there and they won't charge you for that.
What they charge for are interment lists and it is a steep price - I recently paid $180 for an interment list of 19 people. I'd got a family member's details from a death certificate, called Calvary for the grave location and they informed me there were another 18 people in the same plot of 3 graves so I had to pay for that info to see who else was buried there. Plus it's all or nothing as well. If there's X number of people on the list you can't ask them just to check if another person is on that list - you pay for X number of people - the whole lot. I wanted them to check if just the husband of the family member above was on the list (I'm unsure of his death details) and they said that for individual searches they need to know the name, month and year of burial.
Good luck.