Honestly, I am not sure if I understand the role of the employer in the WILP course? Is it mandatory that you should have their approval? Does the college insist on that? Have you signed any undertaking with the employer for a certain period of commitment? Is there any kind of assistance (financial or otherwise, such as adjusting the working hours) from your employer?
If the above restrictions are not there, I do not see any issue in pursuing employment outside after the course. As for whether your college will allow such a facility, depends on them. Have a word with them. (I may be wrong – but for WILP students, the college may not even offer a placement program.