Two point is great! And just because you can't ride without stirrups doesn't mean you shouldn't make that a goal of yours! Start small. Don't expect to be able to go a whole ride without stirrups your first time. Start off with a specific limit on it- five minutes, two laps, whatever you want. Make it doable. The more you work at it, the easier it will get. You also might want to consider working out, perhaps running, biking, using an elliptical, whatever works for you. Gaining leg strength is important.
Also, when jumping, really focus on keeping your weight in your heels. Often, when people find that their legs slip back, they're putting their weight ahead of the horse. Make sure to hold with your whole leg, and don't pinch with your knee.