I think you will find your problem is not low pressure but low flow caused by you water supply line from the city water main and meter is too small. The city main has a certain pressure and will supply only so much water through a given size pipe. A pump on your end would not increase that flow. You need to determine how many gpm you need at maximum consumption, what the city main pressure is, what size meter and supply line you have. You usage on one end and the city's pressure on the other are constant factors. You will need to increase the meter size and you supply line from the meter as they are the only variables that you can control.