personally, i would do the job at home, you need 1000 # sandpaper, masking tape, patience and a spray bottle (istree wali). mask it, carefully wetsand the rust off.
apply touch up paint. cheapest way. probably the best way
if you can get rust convertor, then it is good to use it before the paint, this will keep the rust from coming back.
kktraders sell it.
http://www.kktraderspakistan.com/