Hi krowe,
I'm afraid that before 1837, there is no such thing as a marriage certificate. Birth, marriage and death certificates were introduced in 1837 on the advent of civil registration and copies are available from the GRO and local registrar's offices. For events before this, you need to find the entry in the parish registers, held at the local county record office. You will probably be able to order a photocpy or print from the microfilm. However, for marriages you will not get any information about parents' names, etc. This was not included in the entry in the parish register. You could also try ordering the film from the local LDS centre if available. Then you can see the original entry for yourself.
Hope that helps.
Nell
