Hi Fro. You can check out T-RackS (Mulitmedia) mastering software. This will work only if you have decent reference monitors. I have used the mastering suite at Fantasy Records (George Horn) but George retired. I also released a solo CD using Jeff Sanders (CSN, Stevie Wonder, REO Speedwagon, and a bunch of others). Last I heard from Jeff he was in Merced CA. Not sure if he is even working anymore. The most recent projects I did, I mastered myself using T-RackS mastering software.
Not sure if this is very helpful for your situation. I think T-RackS is worth looking into. It is not cheap software, but costs way less than having it mastered at a professional studio. I mixed and mastered the album "Rejuvenation" by Mark Bowers. Rejuvenation is a new age CD that gets a lot of airplay on the new age stations. I used Pro Tools for recording and mixing, then used T-RackS for mastering. As with any project, you want it to sound as good as you can get it to sound, but weigh the costs of getting it there.
I wish you the best of luck with your CD project.