Read this whole section before posting again about mids and highs. There are plenty of suggestions there. Also, read every sticky thread on this whole forum while your at it.
first you could help out your highs by removing those red monstrosities from your trunk. because they arefleemarket junk...
then you could get an amp and a set of components with a MIDWOOFER and a TWEETER and have an amplified front stage. then you could go out and get some REAL subwoofers and call it a day.