Hi There,
It's not Andreas Gliding club you need to contact to fly into the airfield, it's the airfield owners (For some reason AGC are listed as the contact in a number of VFR guides, and they are not). Contact details listed on AMP website:
IOM Airfields - Andreas
The owners of Andreas might be able to give you a lift to the course if you ask when you call.
If you go to Ronaldsway, Manx Flyers may have a car available to loan you, but as it's TT there will be a lot of GA in so someone may have already taken the cars. If you do fly into Ronaldsway, even though it is not PPR make sure you call Manx Flyers before you leave, make sure someone will be about.