(ignore the belt, I am looking to replace that with either the Blacksmithing BoE or the belt from heroic Tol'Vir)
Basically at the moment I am getting hit pretty hard by mobs/bosses in heroics, or more specifically my health is fluctuating too much and annoying the healers. I noticed that my dodge + parry + block are not at the required "cap"... so basically I was wondering what changes I should make in terms of reforging and gemming to reach the cap... or whether it is just worth waiting until I get new gear (a bit tough since I am struggling a bit with heroics other than BRC and VP)
If you are not at the magic number: Try to balance parry and dodge. Parry is over 14% and gets some deminishing returns, while dodge is below 10. It's ok, if parry is a little bit higher than dodge, because of hold the line, but a difference of 5% is probably not optimal.
About your gems: Don't neglect socket bonusses, they give you free ratings. If you have problems to reach the magic number you want to have every free rating you can get. And yes, new ones are better.
Well and asking for advise while your toon is not enchanted in any slot is well obviously a problem.
Don't fokus at a specialy HP value for heroics. Stamina comes free with your gear. Heroics don't one or two hit you. Doing the encounters wrong will kill you. If you do them right, you don't need a lot of stamina.