This is a format I used to do what you're asking:
{LINK Excel.Sheet.8 [drive]:\\[path]\\[filename].xls
[Worksheet]![CellNameOrReference] \a \t \* MERGEFORMAT}
There are a few ways to create this link,among them manually and through the
Insert menu. Creating it manually might take more time and effort but it
helps you learn the "code-behind" for later manipulation.
Manually: The "curly" { } brackets are actually created by pressing the Ctrl
then the F9 key to form a Word field (don't try to type them in except with
the Ctrl-F9 key combination). Then type your info as above between the field
brackets (don't type in square brackets--those are to show how you'll
individualize per your path, file, worksheetname, etc.). When finished,
select from opening to closing curly bracket, press F9 key; if you've
inserted correct path, data etc. in the "code-behind" within the curlies, the
results will show after pressing F9.
Insert menu (this is from a Word 2003 perspective; probably different if you
have 2007): Insert-Field, then select Link from the "Field Names:" list. In
the next column, Field Properties, type in the path name and file, then
choose Excel.Sheet below that. In the next column, take your choice of Field
Options. I would recommend the ones for automatically updating (first on
list) and preserving formatting (bottom). After pressing OK, the results of
your work should be shown. To toggle the "code-behind" and viewed results,
select the field and press the Shift and F9 keys.
Have fun, and let me know if this works.