A High Jump without a 20 ft. running start:
All Jump DCs given here assume that you get a running start, which requires that you move at least 20 feet in a straight line before attempting the jump. If you do not get a running start, the DC for the jump is doubled.
A high jump is a vertical leap made to reach a ledge high above or to grasp something overhead. The DC is equal to 4 times the distance to be cleared.
So she could make a Jump check, and divide the result by 8 to obtain the number of feet above your height that she managed to get to. It will probably not be very phenomenal, unless she has a very high Jump skill.
You may argue being able to help her (Aid Another action) but that's only a +2 to her roll (or 0.25 ft.).
It might be more helpful if YOU were jumping first, your ally would probably need some Balance check as she is precariously perched on your shoulders, of course, but she could then jump from your high point. Given your Strength, and if you were taking a running start, you could probably clear a couple more feet (although... the rules for Jump are made for Medium character, it would be logical to double the number of feet cleared each time you double in size, but that would be a House Rule).
You then apply the gliding rules.
As far as I know there is no innate ability to throw upward, the rules for throwing weapons require aiming at something.
Interestingly, Races of Stone, p. 139 has the Fling Ally feat: pick up the ally with a Move Action and throw with a Standard Action, but all the feat does is giving a range increment and avoid the Attack penalty for using an "improvised weapon", the character still has to aim for a square, and the penalty for missing is not too adapted to the situation.
If you miss the target (whether aiming at a creature or a grid intersection), roll 1d8. This determines the misdirection of the throw, with 1 being straight back at you and 2 through 8 counting clockwise around the grid intersection or target creature. Then, count a number of squares in the indicated direction equal to the range increment of the throw.
A character with Fling Ally and Improved Rock Hurling throwing another character 2 size less than her (or more) throw the smaller character with a 40 ft. increment (and 5 range increment) so up to 200 ft. upward if you wish, and if missing (by 5*5ft.), you may "only" throw 175 ft. upward if you decide to apply the miss vertically, or otherwise always reach the target height if you apply the miss horizontally.
All in all, I am afraid that this is not helping much. You might want to invest in perch for your flying