Upgrade 09 Specialized Allez double

[Woolski]

First post here,

Looking to upgrade my bike...specialized allez
last year I replaced stock wheels with easton ea50 wheels...and it was a nice change...
I also replaced the stock pedals with look keo classics...also a nice change..

I am now looking into upgrading the seatpost and maybe the saddle?....300 dollar budget..
any thoughts on most important upgrades?

I ride about 300 miles per month....looking to do to a couple of centuries this cycling season...

any feedback
greatly appreciated