Extend duration of title slide and overwrite video but keep audio.....

Likely a complicated one this one.... and may not be possible... but here goes!

I have downloaded a file of the old "Pearl and Dean" music..

When i play it on my project it also shows the graphic with the  "Pearl and Dean" name and the asteroids...

For anyone who doest know it, here it is: https://youtu.be/WUFxARB880E

Ideally I would like to edit the movie so instead of the words "PEARL & DEAN", change to something else.... but this i feel is too tricky to do....

In absence of that, what I would like to do is remove the video attached to the music, replace it with my own title slide and extend the duration of title slide to the duration (which is 18 seconds).

I've not found a way to extend title slides, i have managed to shorten them by using the scissors.

Attaching a screnshot for context.

Any advice appreciated!