Upgrading camera & Can't decide

I bought a canon t3i almost a year ago just to shoot skiing with. After using it I began to really enjoy photography and now I feel have reach the limitations of my camera and want that extra quality a nicer full frame camera would bring me. I have basically narrowed it down to a canon 6D or Sony a7. If anyone has experience will both and could let me know which is my best bet or any other options. Would be nice to stay with canon because of the lenses I want to keep, but I know about the Sony adapters so if anyone has experience with those adapters and which route would be better to go that would be appreciated. Thank you media and arts for teaching me most everything I know and +k to all who help.

1) What is your budget? How much money can you spend right away, and do you think you can get more money to invest in the future?
$750-900 and I will have more money to invest in the future.

2) What experience do you already have with cameras? Have you ever even used one before? Have you helped your friend out with his camera? Have you owned your own?
I know my way around my camera pretty well and help other friends out with theirs often. I also owned my own t3i.

2) What gear, if any, do you currently have? (tripod, old camera lenses, mics, etc)
tripod, x-grip, canon 17-40mm f4L & canon 50mm 1.8 are the only lenses I plan on keeping.

4) What are you planning to shoot and how do you want to use your camera? Are you going to use this with the sole purpose of shooting skiing? or do you think you might try other stuff as well (movies, documentaries, short films, etc)
I will use it probably for 70% photo and 30% video. shooting skiing and skateboarding and maybe some short films along the way.

5) Do you want a camera that you can hand to your friends, that could or could not have film experience, and let them shoot you? or will you be doing all the filming?
I'll be doing 90% off the filming.

6) When filming skiing, how do you tend to shoot? (follow cams, leave it on record on a tripod and hike, film from a tripod, etc)
mostly follow cams

7) What computer do you currently have/use to edit (if not currently editing, what would you most likely use)? If you can provide specifics, such as hard drive space, RAM, processor size, that would be great.
don't know specifics just a mac book pro that's a couple years old.

7) What program do you currently edit on? How familiar are you with it (1- just learning; 10- I can make tutorials and know the keyboard layout)
6 with photoshop skills and learning to use Lightroom currently.