It's impossible to say for certain what her actual score was. However, it seems likely that it was between 60 and 64.
The highest score she could have possibly had was 64 points.
We know that Harry and Krum were tied for first place after the first task, with 40 points (Harry received scores of eight, nine, nine, ten and four in the first task):
'You're tied in first place, Harry! You and Krum!' said Charlie Weasley, hurrying to meet them as they set off back towards the school.
Harry Potter and the Goblet of Fire, Chapter 20 - The First Task
The most Fleur could have possibly scored in the first task is therefore 39 points. With the 25 points we know she got in the second task, that would put her total after the first two tasks at 64 points.
The lowest score she could have possibly had was 36 points. This would require the winner of the third task to receive fifty points, and the others to receive none. However, as there'd seem to be no means of identifying who came second, third and fourth once the Cup had been touched by the winner, this is the most likely situation.
A total of 36 points after the second task would have required her to score 11 points on the first. That would be a particularly bad performance, and would have no doubt been mentioned. As it wasn't, I think we can rule out the possibility of a low score in the first task.
From Ron's description of the four Champions' attempts at the first task, Fleur likely received a similar score to Cedric (who seemed to suffer the worst injuries during that task). A total of 60 would require a score of 35 on the first task, which is an average of 7 per judge.
