i am doing job and as well as i want to do cat exam preparetion

opt for batch which suits your free timings try to join in institutes like ims, time etc. as you have work experience that will help you to get admission in good college

You have the following options 1. Take up correspondence course and prepare yourself as and when you get time. 2. Join weekend courses offered by institutes like TIME, IMS etc

its totally upto u...... best of luck..........