Getting more photo stream space

My most recent photos aren't saving to my computer photo stream. Why?

I'm supposed to have total storage of 5.0 GB. Available is 3.4 GB.

Deleting photos from my iphone photo stream doesn't seem to give me more space.

I currently have 573 photos on my iPhone. I've taken many many more and deleted them from my iPhone after filing them into my pc.

I don't understand how this works, I guess.

I have taken some pix that I would like to save ...I would rather not have to 'reset' my photostream yet.

Please advise me.

Thanks.