Make runescape run better new pc

Hey guys ive got about 450-550£ to spend on a new DESKTOP and im wondering if i can get a desktop better then my current laptop with my budget this is my laptop and specs

http://uk.computers.toshiba-europe....roadvision.session.new=Yes&PRODUCT_ID=1058188

its overheating and is pretty slow so is it possible for me to get a better desktop? i already have a computer screen so could i just buy the computer its self for that money and get better rs performance because i got told the technology in my laptop is old now

thanks alot guys im really bad at computers