Welcome to the forum! Ok come on! As already mentioned I don't think you can make your dad move and find a new job (a bit selfish,) however, if you find yourself a riding stables you can learn to ride. Then I think you should get a part loan or ask a friend maybe if you can help her. Keep asking questions on here but always ask question at your stables. Read books, watch educational (horsey) films. Maybe in a biology class ask your teacher about a horses skeleton and body. You need to understand the signs of illness as well. If you do get a horse, maybe the stable your riding at will have a spare stable so you can get help, but remember it is costly. So I believe your question is what do I need? Well you need -
A fitting bridle to suit your horses strength so you don't get injured;
a martingale or breastplate if the horse throws his head up, or down;
a bit to suit your horse;
a saddle that fits the width of your horse;
Riding clothes (long socks, jods, polos, jumpers, coat and bodywarmers;)
a hat that fits and keeps you safe, I suggest a skull with a cap over the top;
Rugs - stable sheet, turnout, heavy and light, stable rug, heavy and light, a blanket, summer sheet, two fly rugs (horses can break these), exersize and competition sheet.
Boots- to protect your horses feet - Ride your horse because he may brush: brushing boots or other things so protect his legs!
Feed- choose the best feed for your horse.
High visibility stuff: Boots, tail bandages, exercise sheet, hat cover, jacket for you;
Bedding- Choose a suitable bedding, there's straw, shavings, shredded newspaper, rubber matting (I'd advise putting bedding over this), sand and others!
Riding boots - You need a pair of wellies and riding boots, keep your riding boots tip-top.
Grooming equipment- You need brushes, look up what you need and how to use them/groom a horse.
First aid - You need four types of bandages, spray and lotion/cream. You need wormers and look up the rest. I can admit my First Aid kit is pretty poor
Vet and Farrier - The vet will check your horse, so keep his number handy in case your horse shows ANY, ANY AT ALL signs of illness! The farrier will come and do your horses feet, so depending on how much hacking you do you will need shoes or no shoes.
Luxury - After all this, now you can have luxury's for yourself. Personally I have only one luxury, a seatbone saver so make sure your horses needs are covered first!