Starter from previous homebrew - When is it ready?

Hello!
I just made my first-ever yeast starter, and I made it from the dregs from four bottles of a nut brown ale I brewed this summer. I plan to make a revamped - hopefully nut brown-ier - version of the same beer.
The original yeast was Wyeast 1945 NeoBritannia. I made the starter last Sunday with a little more than one pint water, 3/4 cup amber DME, and some yeast nutrient in a quart bottle with an airlock. Today is Wednesday.
The starter has bubbled pretty good for the past couple days, and is now going at the rate of one bubble every 4-6 seconds. I have been aerating it - vigorously at first, but more gently now. About 1/3 inch sediment has formed on the bottom, and foam and krausen still linger at the top.
I plan to brew the new beer this coming Sunday, October 2. My concern is whether I am letting the starter ferment for too long. How long can I keep it refrigerated before using it? Will I need to add fresh wort? When and how much? How much sediment should be on the bottom? Should I let the foam settle from the top before I refrigerate it?
Finally - when I brew the new brown ale - can I just dump the yeast starter directly into the wort?
So many questions, but I appreciate the help!

Maybe add some fresh wort today and it should be very healthy and vital come Oct 2nd. With how small of volume you are talking, I doubt you'd need to decant off the starter. If the yeast is ready to drop (put in fridge for 24 hrs if you want), you can decant off the starter beer.

Search for Mr Malty by Jamil. It may be a little aggressive on how much yeast you need, but it should help you determine a proper pitch of yeast based on the beer you are brewing.

Thanks for your help! I think I may actually brew the beer tomorrow (Friday.) In which case, I should put that puppy in the fridge pronto. I won't need to decant very much, but I'll do it for a cleaner, fresher flavor.