Emails and IP Address Correct Settings

Okay; not sure if this is the right place, but I need to start somewhere as my email issue is out of control. To provide some background, here goes... I have a website and my hosting provider uses "c panel" to manage all of my web hosting activities. However my issue is mainly with emails and unfortunately my hosting provider seems to only be able to provide boxed answers in regards to my issues. So I need to take things into my own hands and actually resolve the issues. So the main issues is that Spam Assassin doesn't seem to do anything as I receive 50 plus SPAM emails each and every day... Most are quite clear that they are SPAM so I don't understand why they are coming through. So my first question is how do I ensure that "c panel" and Spam Assassin are actually setup correct. The second problem is that some how in the past my IP Address was associate to SPAM emails so at one point my IP Address became block, so to resolve this I bought a dedicated IP Address. (FYI, I send normal business emails only ie 5-10 day a day and do not use Marketing Email) Not sure about this one as the explanation from my hosting company seem a bit odd, none the less I needed to get this issued resolved so I paid the money to get a dedicated IP address and this was suppose to resolve the issue. Not sure if it did but I know when sending emails to gmail account there are still issues. So my second question is how do I determine if my IP Address is in fact flagged as a SPAM IP Address and that my website and email server are setup correctly and working properly. Okay, that's it in a nut shell for the first phase, once I get this resolved then I can move on to my IMAP format... Hope this makes sense; any suggestion or help would be greatly appreciated. Thanks