Hi. You said that you already have your Google account. You can go to www.plus.google.com and use your login information in the Google. You will be automatically logged in the Google+. Hope this helps.
This link may be helpful for you http://www.zdnet.com/blog/networking/how-to-try-to-get-a-google-account/1233
if you get an e-mail note telling you that you've got a brand, spanking new Google+ account, check the URL for that link before clicking on it. If it's not going to "https://plus.google.com/," or a similar address, don't click on it. You can get your Viagra from a local drug store a whole lot more safely.