at the moment ive pledged 250..,i'm thinking of upgrading so i can play pre-alpha...so what i'm seeing is i'll have to go for the 500.00 pledge now,is that correct?
The lowest package that includes Pre-Alpha access is the Scion of the Black Rose package, which is 750. A difference of 500 if you "upgrade," yes.
https://www.pantheonmmo.com/pledge/upgrade/upgrade-pathfinder/
By all means pledge more to support development - but remember that there is no clear schedule for pre-alpha. Worst case scenario for you is that you upgrade and then they announce that pre-alpha is over and they are working to prepare the game for alpha at some unspecified time in the future.