Hello Swati,
CWA will definitely open good career opportunities both here and elsewhere. I have seen some MBA grads taking up CWA to give a boost to their career when compared to just having an MBA degree. With regard to choosing between CWA and your job offer, consider the career options you will have after completion of CWA and the career growth you will have with the present job. Rs. 17,000 is definitely a good amount to start with as of now (again this would depend on the area/city/region). But you will have to look beyond this before you decide.
With regard to options in CWA, it would be best that you talk to someone who is a practising CWA to get the best possible view. Here I can only give you a brief overview regarding the openings people have after CWA. You get openings in manufacturing industry (since they require Cost and Works Accountants), banking and insurance firms, tax consulting firms, corporates and multinationals, IT (as ERP consultants), etc. In addition, you can start your own consulting firm. So the scope of job opportunities would increase considerably and so does the pay option. Hence I cannot comment on the pay as it will depend on the field you are likely to get into.