You cannot be a patent agent as already been advised above, as science degree is required for the same. You may work in patent portfolio management (meaning - filings, prosecution, renewal, assignment deeds, maintaining files, corresponding with IP offices in India and abroad etc)
Having said that you have plenty of options in other areas of IP to pursue. The formost is TM and CR for sure. Considering your law degree and you get a diploma, the first offers which you may get in any law firm is work in TM and other soft IP (CR, Designs, GI etc) portfoilio management (meaning - search, filings, prosecution, assignment deeds, renewal, maintaining files, corresponding with IP offices in India and abroad etc). You need not have a science degree for TM agent exam. Also, if you are registerd as an advocate, you will not require to give the exam, you may enrol yourself as TM agent directly. As a personal advise, I recommend giving the exam even if you are a registerd advocate as it clears the undertsnading of TM process at a whole new level.
The career options for non science professionals are not however limited to aforesaid. There is huge amount of work happening in the area of IP contracts, licening, agreements; IP audits, training, due dilligence, open source software consulting; UDRP, INDRP proceedings and the list is fairly long. This area is more rewarding than portfolio managment of soft IP discussed above. The only catch is generally companies and law firms prefer an LL.B. with honours in IP or an LL.M. in IP more than a diploma holder for such kind of work.
Then there is always IP litigation, which offers great exposure into the field. There is whole lot of litigation happening in Patents, TM and CR along with confidential information cases. Other kinds of IP are slowly catching up. Also, you do not require a science degree for patent litigation, though understanding of technology helps at times.
Hope this helps,