I Asked my friend out 2 years ago, she said no then but i still have feelings for her, should i try again?

ok so a bit of background, i'm a bloke & my friend is a girl and she split with her boyfriend back in like june 09 and soon after i started to feel more than friend feelings for her so back in about october 09 i mentioned this to her and asked if we could ever be more than friends or date, she took a while to get back to me (i did it by text cowards option i know!) but when she did she said she thought a lot about what i said and didn't think it was a good idea as she was going travelling to australia for a year from april 2010 plus she said she still was not really over her ex, so i was happy to just remain friends above all else obviously, but come valentines day i sent her some flowers anonymously as i could not stop the feelings i had for her and later i asked her if she got anything, think she knew it was me who sent them before i told her i'd sent them, and she was really happy said i really cheered her up, so i thought hey up might be in with a chance once she gets back.

So we chatted by email and i got a few postcards over the year she was away, now shes been back in the UK since about may and we have had a few drinks together and last night just went to a comedy gig together which was great we go to gigs together alot, i love spending time with her and can listen and talk with her for hours, i wanted to say something tonight as sometimes i think i get signals from her to suggest she might be interested but then think it might just be me seeing things that aren't there, so i'm thinking should i ask her out again, but i'm wondering have i missed the chance or should i risk it and try again, without wanting to make things too awkward or put her on the spot again, anyone have any advice as i'm a bit hopeless with this sort of thing?