Sure. The problem seems to be that instead of exporting values to the file you actually try to export the function.
In order to create a list (a table) of values you could use this export command:
Export["~/Desktop/teste.txt", Table[Modulo /. y -> i // N, {i, 0, 0.25, 0.025}]]
The idea is that it takes the Modulo expression and substitutes the y by values in the range from 0 to 0.25 in steps of 0.025. The N helps to obtain numerical values.
I hope that this helps. If you want also the "x-coordinate" you can use:
Export["~/Desktop/teste.txt", Table[{i,Modulo /. y -> i // N}, {i, 0, 0.25, 0.025}]]
Cheers,
M.