Hi Laura.
Well the obvious thing is to push for organizational change and get the whole company on board with SEO and moving in the same direction. That's the best solution as if you're all working together you can pool resources and work cohesively.
But you probably already know that.
To make the most out of your current situation I'd start by doing some onpage analysis - checking your pages are targeted at the right terms and that everything is set up correctly.
If possible I'd push to improve your page types - making sure that your product pages are as good as they can be and packed full of information. That way you might be able to do some linkbuilding to your pages based on the quality of the content.
If not possible then you've got to figure out how to linkbuild to your pages in their current format.
And that's pretty much it - do as much optimization as you can but if your company really wants to move the needle on SEO then you'll be wanting to work on a sitewide level.
Hope that helps.