Renault Clio abs not working and handbrake light coming on

After recently having a new exhaust fitted and new wheel bearings, I am now having problems with my brake warning lights.
The breaks make a strange noise when they are used for about the first minute of the journey after which the ABS light illuminates and the brakes work normally. The handbrake light also came on for the first time yesterday. I have checked the brake fluid and it doesn't seem low so am wondering why these lights are on. I also want to know if how expensive it would be to fix this problem if I need the brakes checking, brake fluid changing etc.

Thanks