The font can be changed in several ways, however this depends on the 'theme' that you are using.
If using a CSS theme then the font can be changed by going to Design | Options | Site defaults and under the properties area change the font value of ACTCSSFONTFAMILY.
If the theme is anything other the CSS then you will have to insert font tags around the variable's where you like to change the font, For e.g. for product description you will need to find the variable the template resides which is Act_Poductline.html look for the variable NETQUOTEVAR:PRODUCTDESCRIPTION and change it to read <font face="Comic sans ms"> NETQUOTEVAR:PRODUCTDESCRIPTION </font>.
I dont use any templates so accessed the act_productline.html as you said, nows its all done. Dont suppose you know the file to access the terms and conditions.
For the Term & Conditions page please goto Advance | Template manager | Other pages and click on the 'Info lines' button and replace the font in that template, for e.g.
Comment