Well, the answer in no definite answer for this since
1) Different Pokemon have different growth rates
2) Different Pokemon yield different amounts of EV's
3) Pokemon yield different amounts of experience
So, the level of the Pokemon you might end up might is too difficult to compute unless I have the exact details. However, I can tell you how many battles it might take.
For Pokemon that yield 1 Atk EV (such as Machop), it will take:
(252 Max EV)/2 from Pokerus * (1 EV + 4 from Power Bracer) = 26 battles
For Pokemon that yield 2 Atk EV (such as Heracross), it will take:
(252 Max EV)/2 from Pokerus * (2 EV + 4 from Power Bracer) = 21 battles
So, if you know the details of the Pokemon who yields such EV's you can calculate how many levels it might take. This and this link might help to determine experience gained; then just apply it to the growth rate or amount of experience needed for a Pokemon to gain a level.
Hope I helped! :)