Squeekers

My husband and I was giving an oval 20 x 12 x 48 intex pool. The pump on it though is horriable. Last year i struggled so much to keep the water looking good and the floor of it vacumed. The pump itself is the one that came with it. It hardly has any suction to it, not even the vacumme it came with can work with it. What kind of a pump do i need to replace it that is good quality, but not break the bank expensive. I have heard of sandfilters needed. But yet that adds more confusion to me. I live in a small town where there is literally no pool or spa place to ask about this. Please help. Thanks.