Make the most of the various European alliances within your family. Part of your marriage treaty included trading privileges. Focus on Scotland's economy. If you produce more local products for export, you can import luxurious items from the Continent.
Attacking the Douglases is a dangerous option right now and would be a huge drain on funds. Try to work out a way of increasing society's wealth without stirring up trouble.
Which card will you play?
Increase the taxes on all goods manufactured in Scotland. With the money from taxes, you can afford to import fashionable European luxuries for yourself and your queen.