Replying to DSLR Gimbal or upgrade to GH4?

So I'm looking to invest some more money into my camera setup this summer now that i'm working again and want some opinions.

I currently have a Panasonic G7 with two fairly cheap lens, they definitely do the trick but better glass would be nice as well. I bought the G7 with those two lenses to check out the Panasonic platform as I was switching from a Canon T2i. The G7 is sweet, but maxes out at 60fps which is definitely a disadvantage, especially since i'm mostly shooting action sports. So my plan was to acquire some lenses that work with it and see if I like the setup.

My question now is what to invest in. I do enjoy using the G7 so i'm not against keeping it for another year or so but I definitely want to upgrade my stabilization. I have a glidecam HD1000 which ive been using for years and have gotten pretty good with it, but no matter how balanced I get it, i feel it is almost unreliable when you only have one chance to get a shot of someone skiing, which I think is where the Gimbal would come in handy.

So i was thinking of getting that and getting a speed booster so i can use my Tokina 11-16 with the G7, which I feel would be a sweet upgrade.

But that upgrade would still lack as the camera isn't cutting edge...so do I spend the 1000$ ish on that, or try and sell the G7 and upgrade to a used GH4 and use my current lenses with that. Not so sure how easy it would be to sell the G7 for a good price.

thoughts?