I'm going to post an answer to what I understand is the real question here, based on your comments above, mainly because the task of parsing an address using Excel functions alone is too tedious. (Trust me, I work in the address verification industry for SmartyStreets and have seen too many failed attempts with simple functions and regular expressions.)
You can continue to try adding commas like this, but you'll eventually find that it's not reliable because addresses come in many different formats, valid and invalid.
We've posted a simple algorithm for breaking an address into its components. It's a different route than where you're going, but you get the same -- actually a more accurate -- result. The problem with your existing addresses is that they are not yet standardized, so performing uniform operations on all of them will yield inconsistent results. (For example, in the address you give above, the "Pkwy" part should be expanded out to "Parkway" because it's not the street suffix; it's actually part of the name. Also, some streets names are numbers, which can be confusing when combined with a house number.)
You said you're missing information with some of your addresses. There are CASS-certified services that are authorized by the USPS to "fill out" the missing data, and standardize them. You can even get mailing discounts by processing your lists through such services. There are many providers, and I encourage you to find an affordable, easy one that you prefer.
One such service is LiveAddress, which will process Excel lists pretty easily and standardize your addresses. Parsing an address into components may be more easily accomplished using the API (if you have some programming knowledge -- but you can hook into it with VBA right in Excel).
Edit: I should let you in on a little secret... earlier last week we deployed a change that allows you to submit just one line (street line 1) to our API and it will still do its thing. This means that you don't have to program that algorithm I mentioned by yourself; instead, just perform the basic request using VBA (just a few lines of code).
If you have other questions about managing your addresses, comment and I'll see what I can do to help you further.