Jan is still the monsoon season in east coast Malaysia. If you want to stay in Malaysia, Langkawi is one option for beach and kayaking.
http://www.langkawi-online.com/

The better oprion is get to Sabah by Air Asia. Http://www.airasia.com

Fly from KL to Kota Kinabalu. Hike the Mt. Kinabalu. Kayak, swim snorkel or bike on Manukan Island.

http://www.abcmalaysia.com/travel/nat_sbh.htm