If you are creating a TOC manually (YUCK!), you can highlight the TOC text,
click "Format", "Tabs", type the "Tab Stop" position equivalent to the right
hand margin setting (like "7.0"), click the "Right" alignment setting, click
option #2 under "Leader", click "Set", then click "OK". Now all you have to
do is place your cursor at the end of the desired TOC label and press TAB
then type the number.
If you are creating one automatically using Heading Styles (YEAH!) under
"Insert", "Reference", "Index and Tables", everything should be automatic
under the "Table of Contents" TAB (right align, leader setting, etc.).
Holler back if you need more clarification.