Trouble with Heroics/OT'ing Kara

[Snake-Aes]

While your gear can and should be adjusted with rep rewards, your armor is on par with your gear level, don't worry about it.

The rep rewards on the uncrushability guides have everything you need, and they make a huge difference. Revered with KoT, exalted with SSO and revered with CE will hand you 4 or 5 slots worth of tank gear.
I wouldn't give you heroic ramparts yet, the mobs there like to stun and stay at range, it's really annoying to handle specially if you're new to it.