Help me out here guys!!!!!!!!?

Allright. From the start i am going to tell you i am probably going to sound like of of those little girls who dreams of having a pony ever since she was born, Well i am one actually:) But i need some advice here.Firstly to start out i am 15 and i have been riding horses for eight years give or take a few. I have been asking for a horse every birthday christmas easter, whatever chance i can use to ask for a horse, i do. I am currently taking lessons once a week with my trainer and riding my aunts horse pretty much every other day. My situation is kind of confusing. My aunt has got two horses 1 is a 15 year old paintgelding that is 15.3. I am showing him in western pleasure right now..The other horse is a 10 year old appaloosa tb mare. She wasnt ridden for about 6 years im currently working with her and she progresses pretty well with her re-training. But now here lies the problem. My aunt is going to be selling both of her horses sooner or later. Tex, the paint is too easy for me, and dolly i could basically train with my trainer to make her better for me. But the thing is she is 10. Do you think i could turn her from what she used to be (HUS) to HUS and western pleasue??? Another Question. I asked my mom if i could buy her but she said she dosnt have the money, y aunt said if she were to sell her to my trainer she would charge 1,000. I asked my mom... If i could save up the mopney for dolly and then get a job to work off the board as it comes in if i could get her, Board i would most likely do livery or whatever it is called where i feed her and clean the stalls myself for 300$ a month. 1000 isnt a solid price but its what ill save up for. How much should i have ready if i do buy her? The barn i would have all things it should have like crossties so i dont need money for that stuff. Here is a list of eveything i have, Full grooming and full bathing kit. Full english saddle and tack, full western show saddle and tack. barn saddle and tack. polo wraps sport boots bell boots draw reins martingale full western show gear. Various fly spray and treatments like thrush stuff. What else do i need and ow much morse should i have ready???????? THANK YOPU SO MUCH!!!!