Since you already fvcked up by agreeing to be friends (you should've said you 'have enough friends already' then cut off contact), I'd say your chances of banging this girl are around 5%. You got friend zoned in an hour after all, what the hell did you do? LOL.
From this point your only choices are:
a) Agree with whatever plans you had, but then flake on her and don't answer any calls/messages. Then the next day or whenever she contacts you next subtly hint to her you were on a date with another girl. This probably has the best chance of working if you pull it off properly.
b) Agree with whatever plans you had, meet up with her and run tight game, C&F, kino etc. ignore the bullsh1t about being platonic friends and go for the kiss toward the end of the night. If she rejects your advances act unfazed and cut off contact with her.
c) Do what Bible_Belt said which I don't really think has much chance of working after the position you put yourself in but it would fvck with her.