Computer help?

Okay so I got my laptop "upgraded" (I thoguth you could add more ram into it but you cant) by removing a bunch of viruses and it kinda made my laptop fast but I wanted to be able to play minecraft but when its "upgraded" its still really slow and laggy? So I want to ask my dad for a gaming PC (Probably a Laptop) but he just got that one upgraded and it cost him $50 so I dont wanna sound pushy and its gonna cost like $800 to get decent gaming laptop what do I do?

What you do is work real hard in school. People that make good grades get good jobs and make enough to buy themselves anything they want.