The easiest way is probably to create a macro in Excel which will output the HTML for a table to a text file. Try this:
Dim rg As Range
Dim ws As Worksheet
Set ws = Application.ActiveWorksheet 'I have forgotten if this is correct, but you get the idea
rg.Select(top_left_cell, bottom_right_cell) 'change for your cells
Open text_file_path_and_filename For Random As #1
Put #1, "<TABLE>" & vbNewLine
For y = 1 To rg.RowCount
Put #1, vbTab & "<TR>" & vbNewLine
For x = 1 To rg.ColumnCount
Put #1, vbTab & vbTab & "<TD>"
Put #1, rg.Cells(x, y).Value
Put #1, "</TD>" & vbNewLine
Next x
Put #1, vbTab & "</TR>" & vbNewLine
Next y
Put #1, "</TABLE>"
Close #1
Set rg = Nothing
Set ws = Nothing
My Excel VBA is a bit rusty, so I expect that's full of errors, but I think you get the idea. Once you've run that macro with your excel worksheet as the current worksheet you can copy and paste the contents of the text file into your HTML. Of course that's a bit crude if you want to do this a lot, but it's fairly simple to extend this example if you want.