Canadian Needs Help (as in good advice)!

We just arrived in Orlando and would like to visit Universal Studios. We have tonight and all day tomorrow. We are staying in a hotel with a free shuttle ride (drop of and pick up only once per day) 30 minutes from Universal. Our trip from Canada was for business but we finished early so we have a few days here in Orlando. We have a rental car but $17US parking is alot....
Recently the Canadian dollar dropped to 75 cents so we're paying an additional 25% + and that limits our budget. We are both adults and big on theme rides...not so much on roller coasters. My wife is very interested in the Halloween night.
So....is it a good idea or practical to purchase the Halloween night for tonight and then a full day at the park tomorrow? Are there any discount coupons or packages out there that would make sense for us?
Help!!! We didn't preplan this!

If they only have one drop off and one pick up per day, I'd splurge and drive to the park. I don't think you'd even be able to get a ride for HHN tonight from a shuttle.

I think I heard there were tickets you could buy with an HHN add-on that might save a little on the tickets. Have you looked at Universal's website for tickets yet?

yes but it looks like it's a same day add-on. I'd like to go to HHN tonight and Universal tomorrow...I don't know if it's possible to do the HHN one night and the theme park the next day