Crusader Kings 2 From Count to a Duchy

I am in a terrible vassalage situation. I am one of various counts you can find in West Francia at the old god start.

I manage to get into West Francia current ruler's good grace briefly and asked for a title at a time when he was over his demesne. Of course I didn't expect anything at that point.

The king of West Francia eventually decide that I would be better off to be a vassalage of a duke that isn't even within my main title's De Jure… Worse yet all of my vassal as council members are somewhat inefficient in their duties (lack of skills).

I am actually my current De Jure largest count (3 direct demesne and one isn't mine which is owned by my Heir Son) in Gascogne while my liege is a duchy in Toulouse which have very few titles to give out (4 demesne, 3 vassalage).

Short of expanding outside of realm. Not much I can do to grow.

I would like to break this vassalage and move into direct vassalage to West Francia or better yet gain the Duchy of Gascogne.

I can not declare war on my De Jure Duchy even if I had a valid CB on the duchy Gascogne title itself because I need to break off from my duchy liege first.

To add salt to my wound, Duchy of Gascogne has 4 sons, 2 daughters, and one Priest (took vow apparently). They are all eligible to inherit more or less.

I manage to switch over to Elective Monarchy until I can move to a better inherit law.

Question: How do I grow as a count at this point or other similar situations?