Hi Kelly,
I agree with Bethany below that you should start to look at how to optimize pages of your website instead of trying to optimize the whole thing at once.
I would really start by looking at the pages on your site that receive the most traffic from organic search. Make sure your title tags, meta description and content contain the keywords you would like to appear for in SERPs while also insuring that the optimizations add value to the user experience (I am not telling you to keyword stuff by any means!)
I would then start to build content around these keywords and topics that add value to your brand. This will help to regain some of the lost position in SERPs and also help to ensure that you are not penalized by another Google Update. I will let you know that this isn't a solution that is going to work over night, but will help your website to build strength for those topics.
After you have built your content I would start to focus on off-site optimization to help get links regardless of what anyone else says.
Sorry this is a really broad recommendation. Let me know if you need anymore detail.