Speaking to my host service they stated its because WordPress is open source and anyone can hack it
Bullshit. You can apply that statement to any web application or server that isn't properly secured or administered. They gave you that excuse because they are not, and do not get paid to be, involved in the security of your website.
this is my 3rd hack in 4 weeks
In all probability, that suggests a pre-existing vulnerability that has not yet been identified and controlled. Upgrading is most likely just a coincidence. Any evidence in your server logs? (been hacked 3 times).
Have you verified that file and folder permissions are correct, and that there are no files or directories present that you did not put there? Inspect the contents of the index.php file in your root directory.
Have you viewed your database for unauthorized admin accounts and users?
3rd hack in 4 weeks
Sounds like you have been hacked just once. It just has not yet been fixed.
an excerpt:
"Just days ago my whole plugin folder on my server dissapeared and though I was able to redo it all I assumed I had been hacked..."
That may indicate something other than a WordPress problem. Have you changed your ftp access info, and WordPress admin account credentials since the first time you were hacked? Only index.php seems to be affected right now, because I can browse any other page on your site normally as long as I don't go to the home page. Give it a try.
http://homeiswherethecarsparked.com/about-2/
Good luck to you.