I had mine break at the block when installing headers. With no luck trying to extract the piece still in the block, I went with a different approach.
I had some steel brake line around that had an OD that matched the dipstick tube's ID. I used it as a splice. Pressed the brake line into the dipstick (on the bench) and "crimped" the dipstick tube a bit to stop it from going all the way in, then just wiggled it into the place in the block. Worked for me.

Now, you can buy a dipstick tube and cut it -- making another cut on the piece in the motor (high enough for you to reach) and either apply the same technique that I used, or even simpler; just use some rubber hose and clamp it together.