Create HTML header that will use any font you need (you can find examples of the headers in “Examples” directory and use one of them as a base for your own header). For example you can insert “style” attribute into <table> tag (e.g. <table border="0" bordercolor="#000080" width="100%" style="font-size: 22pt">).
Open Report Profiles dialog, select the report profile, mark “Use external header” option and specify path to your HTML header.