Need Inexpensive Crossover

I'm using Monitor Audio GR-10 bookselves and a Klipsch powered subwoofer. Right now I'm running them both full range - and using the low pass on the crossover to have it kick in at about 80hz.

What I want to do is to roll off the low end on the bookshelves - as the bass sounds a bit too muddy at higher volumes (and just send the higher frequencies to the bookshelves - say above 80hz)...... and then just send the low frequencies (that aren't being sent to the bookshelves) to the sub (and probably not use the subs lowpass filter at all).

I know that crossovers can get to be pretty pricey, as all high end audio can. However, right now I'm a bit tapped out on the high end audio budget... and need something that will do for the moment - maybe I can upgrade lower.

Do I need something that has both a lowpass (for the sub) filter and a highpass (for the bookshelves) filter. Can one crossover unit combine this, or do I need 2?

I'm looking at spending no more than $100.

Is this possible?

thanks for the help (in advance)