GEORGE, First off, a pump's not gong to do you any good, what you need is a booster compressor (pumps are for liquids, comps for gases). Secondly, I don't think the utility service or the building code inspectors would take too kindly to a user installing their own booster comp.. It sounds as if demand is outstripping available supply (pressure drop in the mains and laterals is a symptom), boosting the pressure is not going to fix the problem, the solution lies in increasing mass/volume flow into the system, which is the responsibility of the utility service supplier.
Hope this helps.
saxon