Yes... Go for both.. SEO is good for long time but if one is generating income using both PPC and SEO its no harm to invest in PPC (it will defenately help to generate more income)..
Both has their own advantages and disadvantages Talking about SEO, we can get huge traffic free of cost if we concentrate on onpage and off page optimization where as in adwords u will get a targeted traffic by paying money which can be benefited for web masters
PPC helps in targeting particular location or people very easily and can get quick results. Where as SEO takes much time for the same. Of course PPC is a bit costlier than SEO, but results are fast. On the otherside, SEO link-building and proper on-page will helps in long run success of a website. I would go with SEO for slow and steady resutls.