volume on burned disc

Play back on computer is good but when burning to a disc the volume on the burned disc is very low.

Before you export your WAV file for the CD, apply the Normalize effect and normalize to 0 dB.
0 dB is the biggest signal level possible without clipping (distortion).
Note that commercial CDs usually use “compression” and “limiting” to force the sound to unnaturally loud levels (see http://en.wikipedia.org/wiki/Loudness_war ). Unless you also participate in the “loudness war” commercial CDs will sound louder than home recorded CDs.