ok so i as understand your dad is gonna get you the graphics card? ask for a gtx 970. i hate using the word "futureproof" but it's about as future proof as you can get because there are no other cards on the market that offer this value with directx 12 features. it's your best bet
your have a 300 dollar budget for mottherboard and cpu? found a really good deal on newegg.
http://www.newegg.com/Product/ComboDealDetails.aspx?ItemList=Combo.1929332
total is 239$ also there is a 10 dollar mail in rebate, it doesn't get any better than that, i'd jump on it
now from what you said you will manage ram and psu, you stated that your 300 dollar budget is separate for that and that you'll take care of it. ok but do note that you'll need ddr3 ram, i recommend 8gb of ram, that's 2 sticks of 4gb operating in dual channel mode rated at 1600. for psu i'd recommend a 650 80plus bronze certified powersupply. you didn't mention case. that newegg deal i mentioned is a full atx motherboard and you will need a case to support it. cases you can go cheap on like 40 or 50 bucks sometimes lower but i like a nice looking case with features. but as long as it's atx support pick what you like really. oh forgot be mindful that the case can fit the gtx 970 it's a rather long card.