Sibelius and plug-ins

hi, first post!

ive had sibelius for a while now and have used it just to make a few compositions as you do.

Then i came across some demos that people had made on a 'hans zimmer' forum which sounded amazing. It appeared that they were using things like East west and stuff like that.

I really have no idea on these things yet decided to 'get' sumin called stormdrum and im in the process of 'getting' ewqlg in the hope that i can liven up some of my comps on sibelius.

My question is can i use this software to make the playback on sibelius and how, or if i need a sequencer to make it all work.