If the proportions of the table talker are the same as the poster, you can make a new document the size of your table talker and place the InDesign file you made for the poster and resize it. Either use the percentage scaling fields or drag a corner while holding Command (to resize) and Shift (if you need the proportions to be the same). If the proportions are similar but not exactly the same, you can drag the corner with only the Command key to fit the poster out of proportion.
If the proportions are way off, or if you don't like the way it looks when either the width or height are not in proportion, you may have to redo the job. There are some things you could try to get you in the ballpark, but expect to do some amount of tweaking. Please post back if you need more info.
Or, do nothing and scale it when you print. Many designs are not made at their nominal size.