if you are mostly interested in good sounding brass, Native instruments' SESSION HORNS is an excellent sound library

http://www.native-instruments.com/en/products/komplete/orchestral/session-horns/

You might find that you can live with the other sounds in Coyote forte if the brass sounds the way you want. This library should work with PT, and it definitely works with BIAB and RealBand.

The main advantage of using something like session horns is that you can edit and arrange the notes because it's still MIDI

However, if you don't need note by note control and mostly want rock solid background instruments that sound totally realistic, the best solution is to buy BIAB in order to get the RealTracks

Keep us posted! We'd love to help you get started using BIAB and RealBand!