Hi
We are actually 3 guys: I work with SEO and overal strategy, Nicolas works with social media and PPC, and Romina, graphic design.
Regarding SEO, in my experience there are some basic things you need to do in a "one shot" job that could be done within a week. And after that, the best way to keep improving search engine position on a monthly basis could be a decent link building as ongoing task (to reputed directories, and setting up a link building strategy according to product type), and a content management strategy that could feed your website with healthy keywords and at the same time drive traffic.
We can also work on social networks and creativity (with the visual components) for social media posts.
And if we agree a monthly fee, I can work on strategy assessment and implementation.
Best regards,
Guillermo