You can get them
here. If you're not comfortable doing the job yourself, which I completely understand, maybe you can find someone else to do it for you. I'd offer, but I haven't done the deed myself, and I'm not about to experiment on someone else's Duo. The long load times do sound like a laser problem, but the audio problems do not. What cuts out - the red book audio, the chip generated sound, or both? If it's just the CD audio, then you probably have dried out capacitors, which is a common Duo problem. Either way, there is no easy fix for your Duo.
TurboStar has a good question. If you're using CD-Rs, then that may be your problem, as Duos are damned finicky when it comes to burned discs. Try another brand of discs, burn at a slower speed, or stick to the real deal.
Back to Ys III: I played through the first two bosses last night. By the time that I got to the first clown, I was at level 5. With the cheapest sword, armor, and shield equipped and with the help of the power ring and a tasty herb, I sliced and diced his ass but quick. Just duck down and stay down to avoid his fire balls and chop him up good. I didn't even really try to avoid the falling swords, as they weren't hurting me as much as I was hurting the him.