If I'm reading your question correctly...

Gmail is accessible using IMAP, and Outlook keeps each IMAP account in a separate set of folders. You can configure Outlook to use a different account for your "Local" folders (where you store POP mail, contact, calendar, etc.). It would be simplest if you already have the first account set up before adding the Gmail account.

Does that make sense?

It didn't make any sense to me, as to how to correct the issue, that is how & what is a IMPA account as well as how do I access those files using firefox

Firefox is a web browser: you can use it to view your Gmail online at google.com. Outlook connects directly to the web without using Firefox at all.

Outlook supports both Internet standard ways of connecting to email accounts: POP and IMAP. For Gmail, the best way to connect is IMAP because then instead of having separate copies of your mail in Outlook and Gmail, the changes you make in Outlook are synchronized with Gmail: if you sort mail into folders in Outlook, they are sorted in Gmail; if you delete messages in Outlook, they are deleted in Gmail, etc.

This article describes the process (not an official Google or Microsoft site, so you may want to confirm with their help pages as well):

Use Gmail IMAP in Microsoft Outlook 2007 - How-To Geek

If that doesn't help, could you describe the steps you tried so far -- and where you stopped because you didn't want Gmail to be your main account?