After looking at the site, and hearing you say there was no manual action, I think your troubles lie elsewhere, as in Google just doesnt like the site anymore due to on page/off page issues.
I'm guessing your site wants to rank for "chiropractor in pickering" or "chiropractor pickering"?
Let's get started (cracks knuckles):
The home page currently has 4 versions.
http://www.drkevinfinn.com/
http://www.drkevinfinn.com/index.html
http://drkevinfinn.com/index.html
http://drkevinfinn.com/
You have duplicate home pages, and need to process a redirect in cpanel/htaccess to prevent this. Here is the code you need to put in place in htaccess after the # RewriteBase /
force www
RewriteCond %{HTTP_HOST} !^www.drkevinfinn.com$ [NC]
RewriteRule ^(.*)$ http://www.drkevinfinn.com/$1 [R=301,L]
remove index.php within the URL
RedirectMatch permanent index.php/(.*) http://www.drkevinfinn.com/$1
remove index.php at the end of the URL and change to /
RewriteCond %{THE_REQUEST} ^GET\ /./index.(php|html)\ HTTP
RewriteRule (.)index.(php|html)$ /$1 [R=301,L]
Remove index.php from root URL
RewriteCond %{THE_REQUEST} ^[A-Z]{3,9}\ /index.(php|html) [NC]
RewriteRule ^index.php$ http://www.drkevinfinn.com/ [R=301,L]
#end code
Keyword selection:
The keyword selection on the pages is pretty jarbled, and could use a bit of cleaning up. For example on home page:
name="keywords" content="DR. Kevin Finn,Chiropractor Pickering,chiropractor services in Pickering">
could be changed to: (DC is the abbreviation for "doctor of chiropractic", CA stands for both Canada, and for Chiropractic assistant, a double benefit!)
name="keywords" content="chiropractor, chiropractic, care, clinic, service, pickering, CA, Dr Kevin Finn, DC, doctor">
Site meta description: Also, the description for the site is not very.....descriptive:
name="description" content="Chiropractic Dr. Kevin Finn offers chiropractor services in Pickering.">
let's elaborate a bit further, based off of your services page:
name="description" content="Dr. Kevin Finn is a chiropractor clinic in Pickering, CA offering chiropractic care and services to clients suffering from back pain or injury.">
On page copy:
On page copy is a bit thin. Your headings list the main keyword and location, but the body copy does not. From the homepage:
"Chiropractors are experts in the diagnosis and treatment of injuries or conditions related to your nerves, muscles, bones and joints and how these conditions may impact your overall health and ability to work, perform and enjoy life.
People most often think of visiting a chiropractor for back pain or neck pain and headaches, but chiropractors can help with problems in the shoulders, elbows, wrists, knees, hips even your feet! Research studies have demonstrated that chiropractic treatment provides excellent relief for these conditions."
^^^^^^^ NO LOCATION LISTED!! Also, the phrase "chiropractors" is used often, but not chiropractor, chiropractic, etc etc and anything else you want to rank for. Many pages only have 2 short paragraphs, which limits how often and where you can link to.
No Interlinking of pages in content.
Google hates dead end pages, and users dont spend much time on them. Add in additional copy, and link using anchor text to those related pages as you talk about them.
No authorship or markup:
http://www.google.com/webmasters/tools/richsnippets?url=http://drkevinfinn.com/index.html
Click-through ratio is probably getting hit hard because of this. You have the google+ page linked in the footer, so what is stopping you from creating the markup? Also, does he have any reviews? I'm sure one or more patients would be happy to write some reviews, and them you can add in aggregate review markup and make the indexed links shine. Don't know how? here you go: https://blog.kissmetrics.com/get-started-using-schema/
Start looking objectively at these areas of your site. I dont think you are being affected by the hack, as much as areas of SEO that need more attention to detail. If the hack was a major factor, you most likely would have received a message from GWT saying that malware was on the site.
Best of luck, and let me know if I can help with anything!