help with choosing Analog to Digital gear please!!!

[Okiwon]

Hello Everyone,
I am building a home studio for the sole purpose of converting some analog cassette decks to digital format. The tapes are of a deceased band who recorded their masters onto cassette 30 years ago outside of the US. These are the "master" recordings on cassette (instead of reel to reel) unfortunately!
Please help me with advice on how to finish the chain...

Nakamichi Dragon Cassette Deck (already purchased)
to
Aphex 124A Line balancer (please advise)
to
Rosetta 200 A/D Converter (please advise)
to
PC (Not Sure how to interface them)

My PC currently has a Sound Blaster Elite Pro (136dB THD+N w/Digital Inputs)

Specifically, I'm not sure what to buy... If I buy a A/D like the rosetta, do I need to buy a PCI card or something to hook it to, or can i just plug it into my Sound Blaster? I could certainly just plug the deck directly into my soundcard, but I want the BEST results and am willing to pay. Any advice would be greatly appreciated!!