Here's some info on parking, including a phone number:
NYS OGS - Support Services - Parking
If you stayed at the
Crowne Plaza, you would be able to leave your car there, and walk to the convention center in ten minutes.
There's the
Holiday Inn Express too.
My personal choice would be to choose one of those two and walk, rather than worry about driving to the convention center and getting lost (the parking garages are a little bit of a rabbit warren) on a day that you're going to want to be there calm and early. The expense of the accommodation might be offset by the increased control over other factors.
When are you taking the exam? This month? If you only have ten days or so to figure out where you're staying you would be well advised to make your decision soon.