How should i propose to my beautiful girl?

I am 26 and my beautiful girlfriend is 24 and i love her so much, i worship the ground she walks on. She is from New York & i am Portuguese but lived there for a year when i met her but have now lived in Portugal for a year and we always fly over to see one another a lot & spend a few weeks together. I have asked her to move out here permanently & she has said she will think about it. I am very wealthy so i can look after her no worries. When i am with her i am the happiest i could ever be, i get her almost anything she wants or could need. She hates that i am always buying her stuff or sending them to her, she says its too much but i love her. When we are together or if i whisk her of somewhere abroad its almost impossible for me to keep my hands off her, she is the most beautiful thing to have come into my life. I call her about 8 times a day just to hear her voice, I am absolutely crazy about her, i only have eyes for her and i need to spend the rest of my life with her. I really want to propose to her and make it really romantic & special. I want her to live with me all the time here. How should i do it? Any advice would be great.