Hullo there,
ScOACC and indeed the New Prestwick Centre are closer to Prestwick Town railway station than the one at the airport, as the centre is not on the airport complex itself.
There are always, or almost always taxis at the railway station if you don't feel like the walk. If there are none there give Streamline a call on 01292 261000
To see where the place is on google Maps check out :
KA9 2NR - Google Maps