Golds were in her hand. She draws 5 before you start your turn.
PeterJohn - Grujah's post is spot on, but may not be clear due to its brevity, or perhaps if you are new to the game. What he is saying is that the 4 golds that your opponent gained to the top of her deck during her "turn" were drawn into her
new hand (along with a fifth card of course) immediately after her cleanup phase, and therefore (just) before you started your turn. They were therefore not on the top of her deck when you played the Noble Brigand, and you got to see what the top two cards of her deck were at the time you played the NB.
If you've played IRL you know probably know that the game's mechanic is described in the rules as "ABC" - play an
Action,
Buy a card, then
Clean up. I teach new folks that there is a "
D" phase -
Draw your new hand. As others have posted, your turn is not over until you have drawn your new hand.
Hope this helps. Welcome to the forum and to Isotropic. I think you will find this community very civil, helpful, and fun.
Edited to fix typo and to add the final sentence to paragraph 1.
Second edit: To insert the word "new" (in boldface) in sentence 2 for more clarity.