You can't enter HCs before you've killed Garrosh on normal(Or bring one that has killed him on normal)
Your gear is high enough, and the damage is okay too for HC. we're about the same timewise, with raiding 5½ hour pr week, and we ended up taking 2 hours extra one week to get it cleared.
If you extend the lockout you should probably be prepared that you won't get it down that week.
Blackfuse might give you some trouble. Is about getting the transporter working well, and tanks killing the adds right.
Paragons was easy for us, but overall require tanks to do it right. Took us 4 pulls.
Garrosh is hard as in people need to play well individually, but if they're good at mechanics it shouldn't take you too long. And you want to 2heal that fight. Don't think your dps is up for 3healing that fight.
I would advice you to go do those bosses on flex first if you haven't, since you then can get a good part of the mechanics in place.