This will get moved to a more appropriate forum shortly (Coffee Machines >$500 probably), so the people helping you probably have more experience with the particular machine, however in the meantime...
What beans are you using - ie; where bought from, how fresh are they, etc. This can play a huge part in coffee extraction. If Supermarket beans, I would say that is probably the majority of your problem. If they are fresh beans (ie; from a local roaster, roasted yourself or through BeanBay...not from a cafe that may have had them on the shelf for three months), then Ill let people that own or have experience with your particular machine take over...