You can use the -Fragment parameter.
$pcName = "Computer Name: $strComputer" | ConvertTo-HTML -Fragment;
$biosV = "BIOS Version: $objItem.BIOSVersion" | ConvertTo-HTML -Fragment;
ConvertTo-HTML -Body "$pcName $biosV" -Title "List of Computers" | Out-File c:\listofcomputers.html
Just create variables after the Write-Host with the same content and use the converTo-HTML at the end of the script.
This way allows you to style your HTML output too by using the param tag or even table tags to have a better layout then a clean sterile layout.