Here is a page I wrote about this on my website - I'm no expert, and it's a bit longwinded maybe, and there are very likely better ways of doing stuff in it, but it might be helpful. Making a CD from a tape is not at all hard to do.

The quality of the resulting CD depends on how good the cassette is in the first place - though you might improve on that a bit, since in the process of making it you can get rid of the some unwanted noise, fade in and fade out, and change the order of tracks and so forth.

And once you've made one you can easily copy as many as you like as and when you want them.