You might want to look at the Everything About WDW Tickets locked sticky in the TPA&S Forum. Especially the items bolded in the list below.
Post and Contents
1. This Table of Contents
2. Magic Your Way (MYW) Ticket Basics Including Definitions
3. Annual Passes and Water Park Tickets
4. Tickets Available Only to Florida Residents
5. Tickets Not Available to the General Public
6. Upgrading MYW Tickets (Not to Annual Passes)
7. Upgrading Tickets to Annual Passes
8. Dealing With Tickets Issued Prior to 1 January 2005 (Pre-MYW)
9. Children and Adults
10. Special Events
11. Comprehensive MYW Ticket Example
12. Hotel Card (Key To The World (KTTW))
13. Lost Tickets
14. Finger Scans
15. Frequently Asked Ticket Questions.
15A. Hopping Rules
15B. WPF&M With No Expire
15C. No Expire Upgrades
15D. Upgrading an Unused Ticket
15E. Upgrading Special Tickets
15F. Checking on Old Tickets
15G. Renewing Annual Passes
15H. Upgrading a Completely Used Ticket
15I. Getting Park Tickets Before Package Start Date
15J. Upgrading After Departure
Page Two of the Sticky
16. Resident 4 Day Wild 4 Disney Pass
17. 2011/2012 Armed Forces Salute Tickets
18. Prices Effective August 5, 2010
19. "Free" Tickets and Special Promotions
20. Ticket Purchase/Upgrade Locations and Telephones
21. Florida Resident Installment Purchases of Annual Passes
To get there directly, follow the link in my signature.
The thing to be aware of is if you want to upgraded to a ticket which has blockout days, such as the SP, you can do it on a blockout day provided you did not use the ticket that day. So if you will follow this procedure, you cannot use the ticket the last day of your stay and still do the upgrade.
Why not go for the extra $120 and get a full AP which has no blockout dates and includes parking. Note you can use the value of your seven day ticket as the down payment for the Monthly Payment Plan.
