You could try doing a vector trace in Inkscape but you'd need to do a bit of clean-up most likely. Probably for a piece this simple it'd be easier to trace it by hand using a pen/ bezier curve tool. Don't have much to comment on other than the hand could probably use a little work.^ ive seen wolfenoctis do this with the pen tool in photoshop and it came out rly cool, and it was alot more detailed than this so it should be really simple to turn this into vector.
I fixed Lennon's Harry Potterness
I fixed Lennon's Harry Potterness
it still super looks like harry potter to me dude, its the clothes too -