Well, this is a total hack, but it might be worth a try. If it works, it'll be really fast. If it doesn't, you won't have wasted much time.
Create an empty duplicate of your target table. (Right click the table name in SSMS, then Script Table As -> CREATE To -> New Query Editor Window; then change the name of the table, ditch indexes, etc. Just make a heap.)
Once your copy of the table exists, right click on that and select Edit Top n Rows.
Go to Excel. Highlight all of the cells you want to bring over and Copy them to the clipboard.
Back to SSMS. Select the full first (empty) row in the editor window (click on the arrow to the left of the row).
Hit Paste.
Depending on what kind of data you have, there's a fair chance it'll drop right into your heap. From there, you can just do an INSERT back into your base table.