There are two possibilities you may want to consider.
1. Get a drive that will read both CDs & DVDs.
2. Get a drive that will read both CDs & DVDs, plus burn CDs.
My G4 AGP came with a CD & DVD reader, I replaced it with a drive that also burns CDs.
Bought it from Other World Computing for $39.99 + shipping. Here's the description.
Apple Logo Phillips CDD5301 (The drive is bootable)
32X CD-R
10X CDRW
40X CD-Read
12X DVD-Read
1 yr warranty
Send me [ caltx(at)flash(dot)net ] an email and I will email you a copy of the G4 Service Manual which will give instructions for removal of your current drive & installation of a new drive.