u wouldnt be able to get much for it, i would suggest just using it for now to do what u want, u can still play okld games and a bunch of RTS on it. and if u like cs (best fps in the world) ul be fine with that comp
once u get a new comp u and ur buddies can plan LAN with that dell, along with alot of otehr stuff.
i woudl suggest not selling it for the maybe 40 dollars its worth and use it till u get another one
i also am in high school, i had a part time job making same as u, i saved up for about 8 weeks and bought super pimp comp... so just wait a while