Does the laptop appear on the network and work within the network? Meaning the only issue is the lack of an internet connection....
Make and model router and repeater?
Check the respective User Guides and Manuals to ensure that you properly connected and configured the wireless repeater.
Did you connect router to repeater via LAN port to LAN port?
Is the laptop still configured to obtain its DHCP IP address from the router. Repeater's DHCP should be off.
Run "ipconfig /all" (without quotes from the laptop's command prompt. Post the results.