Personally,I'd get a pup,bond with it ,train it put every bit of time in to it
Let it pick up everything off the old bitch,
Think long term,I know it's hard,thinking about not having a dog ready but if you can get another season out the old bitch,and put a lot of time into a pup I'm sure the rewards would more than pay for the waiting now,
Just my opinion,as I've done the older dog thing and found it hard to bond,yet a pup you've brought on you will give all your spare time to.
Good luck it's nice sometimes to have a quandary!