Upgrades are hard to get and never guaranteed and in my view should never be the basis of selecting a ffp. You will end up being extremely disappointed most of the time. Success can depend on many factors including airline status. As a frequent spender and not a frequent flyer guessing you have no status and will not get status

For upgrades the general rule is you can only upgrade a flight marketed (flight number) and operated (metal) by the airline of your frequent flyer programme (no codeshares) with your airlines upgrade instrument (e.g. SWU, miles) or complementary with status (if applicable) or ff miles/cash. All subject to the t&c's of your FFP and your paid ticket. Low cost tickets are often not eligible for upgrades.

Cross airline upgrades are uncommon. If cross airline upgrades are offered they tend to require a very expensive base economy fare.
http://www.flyertalk.com/forum/ameri...aster-thd.html
http://www.flyertalk.com/forum/unite...-carriers.html

Look here
http://www.flyertalk.com/forum/ameri...l-program.html
http://www.flyertalk.com/forum/infor...help-here.html

Edit
For information. Note posts 2 & 4 http://www.flyertalk.com/forum/other...e-upgrade.html