im nowhere near high enough to help, but heres hoping you succeed in your attempt 
Well, I've a lvl 41 Kin Corruptor, which is great for attracting Granite Brutes, gimme a tell at @chi if you think it would help.
TBH, 3 lvls in 7 days is perfectly doable even on your own missions, depending on how long you can play for.
Good luck.
3 lvls in 7 days? er.. ok.. a good (skilled+balanced) will easy kick 1 lvl in 3-5 hours (and yes, all in same lvl +/- 1) if u get a thermal and a kin corr on the same team, rest in team will become a killing machine with endless end/HP and boosted dmg/acc.. thats a very good start 
Hmm... if I can find and badge new contacts for my corruptor Lycricia (level 44 atm) I'd like help you, but that is a big if: I know two contacts from my level range who would give me missions and both of them want to see certain badges before they even consider talking to me 
When I have loads of new missions I'll give you a shout
Basically, I'm after a solid team to help me gain three levels in seven days.
<_<
I'm off to Florida in a week, and really want Eressos at a decent place I can "leave" her, as I'll be away for a fortnight.
I would put in some serious grinding by myself, but I've been doing that a great deal already so the experience is fairly lonely, heh. Eressos is a level 42 Merc/Traps/Scorpion Mastermind for whatever it's worth.
Just a shout out to see if anyone's up for forming a temporary team; although some might call it power levelling.