Look for the following lines (appx 236-255), notice the lines in green. That's the window currently being opened with height/width of 400 pixels each. Now see the lines in red, they use height/width of 450 & 525 respectively (almost what you're requesting). So the simplest method would be to use openWindow(5) where Anon suggested openWindow(4).
"function openWindow(url) {" & vbNewLine & _
" popupWin = window.open(url,'new_page','width=400,height=400')" & vbNewLine & _
"}" & vbNewLine & _
"function openWindow2(url) {" & vbNewLine & _
" popupWin = window.open(url,'new_page','width=400,height=450')" & vbNewLine & _
"}" & vbNewLine & _
"function openWindow3(url) {" & vbNewLine & _
" popupWin = window.open(url,'new_page','width=400,height=450,scrollbars=yes')" & vbNewLine & _
"}" & vbNewLine & _
"function openWindow4(url) {" & vbNewLine & _
" popupWin = window.open(url,'new_page','width=400,height=525')" & vbNewLine & _
"}" & vbNewLine & _
"function openWindow5(url) {" & vbNewLine & _
" popupWin = window.open(url,'new_page','width=450,height=525,scrollbars=yes,toolbars=yes,menubar=yes,resizable=yes')" & vbNewLine & _
"}" & vbNewLine & _
"function openWindow6(url) {" & vbNewLine & _
" popupWin = window.open(url,'new_page','width=500,height=450,scrollbars=yes')" & vbNewLine & _
"}" & vbNewLine & _
"function openWindowHelp(url) {" & vbNewLine & _
" popupWin = window.open(url,'new_page','width=470,height=200,scrollbars=yes')" & vbNewLine & _