horns are tricky when it comes to vst but some options would be a library for kontakt i.e. chris heins horns, or vienna's brass series (they also have a kontakt library), or saxlab. check kvr for brass
even if you get a really good vst, whether it's modeled or uses samples, the real tricky part is playing it in a way that's either believable or at least not cheesy. the next step is making sure it isn't too thin, keeping or creating some dynamics, and mixing it properly so you don't get masking and other freq related problems