Traffic and Sales Cut In Half...Help!

Hello:

I run an online business from which I sell my music instrumentals to artists/companies for their projects. The company had been doing great...it was a 6 figure business after its second year. It continued like that for another year and a half, and since then, traffic, and thus sales, have been cut in half.

I really think that my business was a victim of Penguin, as the link building methods that I had implimented at the start of the business called for lots of anchor links with keywords in them. I've heard that Google since expects only roughly 20% of anchor text links to contain an exact main keyword phrase, and since my site was more near 80%, I'm assuming this is a big reason for the hit.

Anyway, I am just looking for a bump in the right direction to get the site back on track. I would appreciate it if someone could assess the validity of the following methods I plan to use, as well as offer any additional advice for my campaign:

1. Purchase an expired domain that has a PR4 or PR5, and set this site up as a blog/article database which is relevant to my main site. Monetize this site with adsense, but more importantly, load it up with quality content and build links to my main site on it. Also, add some banner ads to my main site on it.

2. I currently do absolutely no forum marketing. Is this still considered to be a worthwhile method to drive traffic and obtain new customers?

3. My main site has a blog on it, but I seldomly use it. Begin making unique blog posts on it, optimized for tons of long tail and even broad (though our site took a big it, we are still considered to be in the mix with the top competition of the niche, so I figure we can rank for some broad KWs too)

4. AdWords campaign? I have always been VERY...I guess cynical would be the word, about AdWords. I understand that being successful with AdWords can be a full time business in itself. Or am I mislead? Would love some thoughts.

5. Content is always king, so continue making better and better instrumentals for my site.

6. I've got a list of over 300,000 opt-ins, but only send an email out about once every month and a half to avoid being spammy. Should I be using it more often?

7. I have an active Facebook campaign that was started very late into the life of the site. It's got around 3,000 fans but nothing to write home about. So, would love some ideas for getting more Likes. Same with Twitter.

8. I would LOVE some valuable input on whether or not something like SeNuke or a similar program could help to drive traffic, or if it would end up hurting my site. If the latter, any other software or things I could outsource on Fiverr/similar site to automate any part of my campaign?

I'm sorry for the long post, and I don't expect anyone to addresss this whole post, but if you could offer advice on (a) the validity of any/all of my aforementioned traffic strategies and/or (b) things that I did not mention that will surely add value to my campaign.

Thank you so much for any help!