Just installed a new windows xp sp3 on my Toshiba Satellite M305-S4820 and lost my audio.Someone please help me find its audio drivers.

You need to reinstall your sound driver.
It will be available on the Toshiba site.

Here are all the drivers for your model:
Model Content Page

Hi, please make sure your computer has a sound card.

You must be logged on as an administrator to perform these steps.
1.Open Device Manager by clicking the Start button , clicking Control Panel, clicking System and Maintenance, and then clicking Device Manager.* If you are prompted for an administrator password or confirmation, type the password or provide confirmation.
2.Expand the Sound, video and game controllers category. If a sound card is listed, you have one installed. If no sound card is listed, You will need to install one.
3.If there is a yellow question mark next to the name of the sound card, there might be a problem. Right-click the name of the sound card, and then click Properties.
4.Click the General tab, and then look in the Device status box to identify problems with the sound card.
Hope it works for you.
Joy fax