Guilds will look at more than your itemlevel, if you present yourself in a way that lets them.
Read this before submitting any applications.
http://www.tankspot.com/showthread.p...Into-Any-Guild
That being said, just because you CAN get into a serious raiding guild with a well written application doesn't mean you should, find one that fits the amount of time your willing to spend improving your character, getting into a guild that's too serious will only waste your time and theirs.
For gearing, don't discount PvP items, capping your Conquest points every week will speed up your gearing process significantly, and 483 pieces are
very good for a raider just starting out and obtaining them is not subject to any RNG drop chances etc.