When is the right time?

I've got a friend... I've known her for nearly 3 years now, and she's become really close to me. I've just recently came out of a relationship, and I've started liking this friend of mine. I liked her before my previous relationship, but I decided to just try and meet some other people for the time being. All in all, I'd say I've liked this girl for around 2 years. I just, don't know when the right time to ask her is. I've only been single for approximately 2 months, and I don't want her to feel like she's just a replacement for my ex. Also, how could I ask her out? She's the type of girl who'd like it if I did something sweet and romantic, but it's gotta be shocking too.. Many thanks in advance. <3