I second the Bryston, second the Blue Circle. Also try Simaudio Moon amp/pre, and McCormack (either the new style or the old). You might also want to look into Audio Research. Don't know about the Musical Fidelity, but undestand it's the big value play. Proceed amps are worth a look too. And of course, there's always Classe.
A resource to look at is Audioreview.com's pages where you will find lots of amp/pre reviews. If already initiated, ignore the suggestion. If unitiated, I urge extreme caution, everything can't be 5 stars, and the truly objective report is the exception rather than the rule. Overall the mood is 'I-listened-to-it-sounded-unbelievable-can't-do-better-for-the-money!' (drunk from hookupitus).
I respectfully disagree somewhat from the implication above you're in need, possibly, of another DAC, as that CD player does digital about as well as any unless you are aiming for the outer reaches of the audio solar system. Certainly anything can be improved upon, but you might just as well be happy on the front end.
Enjoy the search.
Chris