If you are carrying out renovation work, then it would be best to go for the drilling and pumping chemical method. much cheaper then baiting method. That's the method I used.

The drilling & pumping in the the chemicals is very much cheaper as compared to the baiting method. I think it should be about 1k or less depend on the chemical used (for intermediate terrace house)
The pumping of chemical into the ground is more of a preventive measure. While the baiting method is used when your house is being attacked by termites.
So, the method to be employed will very much depend on your situation.

sorry to break this to you... looks like your house is under attack. better get the professionals to take a look and give you their quote. better ack fast before more damage being done. better act fast.

In my opinion, you should get rid of the termites first before you carry out your renovation. Else the termite could attack your new timber material. Unless your renovation works is limited to non timber material.