gerberand
What computer operating system is your Premiere Elements 12 running on? Have you updated from 12 to 12.1 Update yet? If not, please do so. Just background information need for now.
For now I will assume Windows 7, 8, or 8.1 64 bit.
Premiere Elements 12 Expert workspace
1. fx Effects/Audio Effects
http://help.adobe.com/en_US/premiereelements/using/WS4B8135DA-083C-42eb-B09E-65070ECBC889. html
(link should apply to versions 11 and 12)
2. Right click Timeline audio clip, select Audio Gain, in Audio Gain dialog (also has option to Normalize)
Please let us know if the above is the information that you sought.
Thanks.
ATR