Both MI-28 Havoc & TAI 129 are dedicated attack helicopters. TAI 129 is a derivative of Augusta Westland A-129 Mangusta whereas Mi-28 developed from the Mi-24 Hind. Later improvements probably had the benefit of the Russian Afghan war experience. I would guess that both helicopters would cost the same. Unless some on has a mole in the or Joint Staff office, it is difficult to guess which attack helo PA is going to go for.
Mi-35 on the other hand is a direct improvement upon the Mi-24, therefore also has some transport capability. IMO Mi-35 would be far most useful in fight against the Taliban; where it can fight its way in & out of the hot zone to reinforce the troops and/ or evacuate the casualties. Besides, Mi-35 has some commonalties with the existing PA Russian fleet because Mi-24 was the attack version of Mi-8 hence easier to maintain.
Personally, I would go for a couple squadrons (say 30) Mi-35’s immediately and worry about TAI-129 & Mi-28 later. However, if I must decide between these two, I would go for Mi-28, again for purely practical reasons. PA has a lot of Mi-8/ Mi-17 and hopefully Mi-35 soon. It should be easier to induct Mi-28 than a totally alien machine.