Your best off filling at your local site but if you get a dive tank and a fill rig you can do it yourself then fill the dive tank at a dive shop or at a tourny by h-pack who supply the best air for paintball bar non.Ghandi.
^^ They should answer your question. The generators to fill up tyres at garages operate at about 100-200psi, whereas air tanks for paintball are often a minimum of 3000psi.