Regardless of how many gallons per minute a pump is capable of pumping, the shower head on your shower, the kitchen faucet, and even the flow of water in your toilet, all have step down or restrictive water savers built into them that will permit only so much water to flow. Any water pump or water source (if plugged into a garden hose) will not change the amount of water that comes out of the end of your faucet. So, might as well replace with just about any water pump that fits your budget.
Don't believe me, remove the shower head off your shower and catch the water in a bucket. Time it and see how long it takes to fill. Now do the same thing with the shower head on, and you'll find it take twice or even three times longer to fill the same bucket.
