@gemoody, You're probably not going to like what I tell you. Most people find that speakers 'wake up' or 'come alive' when you crank up the volume because fine detail is obscured or missing at low SPL.
If I'm not mistaken only @asctim has mentioned room acoustics. Forget EQ it can't solve your problem. Sort out your acoustics and introduce at least two subs which will allow, when properly set up, room filling sound with all micro detail intact and bass that will amaze with its tight informative performance.
Note: I mentioned properly set up. To achieve this get yourself a microphone and download the free REW from the net. The mic. will set you back about the cost of a decent meal. Too much to go into here but it's the only way to elevate what you have. I do not think you need new anything because your room will not have changed therefore neither will your sound. Sorry to inform that new speakers will just supply a slightly different perspective on you existing issues.