Congratulations.

Cars I found that you can contact a cars club and ask if anyone would drive you to the ceremony. Lots of them love to get the car out and about with lots of people checking it out. A friend of mine spoke to the local car dealer they let her take a car for 1/2 a day test drive. After the ceremony one ofthe guests drove it back to the lot.
Or just arrive in our own car park around the corner and walk in.

For a cheaper dress i would recomend a second hand dress. Then find a dressmaker to adjust for you size.
Mine is sitting in the wardrobe all your welcome to buy that.

Keep us posted on how the planning goes, everything.

Mel