What's GS req for VOA?

I wanted to know what gs is VOA.

Also can someone recommend me what to do to gear up to 5.4k gs?

Let's go with usual PUG requirements:
5K for VoA 10 (4.7K should be ok, but don't expect many invites)
5.4K for VoA 25 (though you should be able to get spot even at 5K)

Gearing up to 5.4K GS:
FoS PoS HoR HC's
ToC 10/25
ICC 10 "alt" runs.
Emblems of Triumph: Usually 2p T9, but if the tier bonus isn't appealing, consider using FOS/POS/HOR HC counterparts.