I have two questions:
1) The mosque I go to, to read Qur'aan I think is a Bralwiya mosque. There is a man there they call Peer Saab, and they say he controls the jinn, and knows when one is lying and telling the truth, just by placing his hand over their forehead. And also they celebrate something they call Meelaad an-Nabi, where they celebrate the Prophet's birthday. Shall I leave the mosque? My mum says for us to go there to read our Qur'aan and come back and not to follow their ways, as there are no another mosque school near our area. What is the best action to take? Also I pray Asr there at 6.00 pm with them, does my prayer become invalid?
2) What is Wahhaabi? Is Wahhaabi the correct sect to be following? Imaam at Grand mosque Masjid Haraam are Wahhaabi aren't they?

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.

It is known that Bralwiya is a Sufi deviated sect whose false ideologies include associating partners to Allaah. For instance they believe that  the Prophet is an absolute assistant to Allaah, and that the whole world is under his control, his order is irrefutable and no one can review or comment on his judgment. They deny him being a human being; as they consider him as a light of the lights of Allaah.  They urge their followers to call upon the Prophets and Walis (pious people), and other false beliefs. Whoever believes in this wrong belief becomes a disbeliever, and goes out of the fold of Islam. Therefore, if this mosque which is near you is a mosque for this group, and the Imaam is from them and believes in this belief, then the prayer behind him is invalid, and it is an obligation on you to pray in another mosque otherwise you should pray in your own home. In addition to this, you should not go to them even to learn the Qur'aan, as this is a danger on your own belief which can be affected by some of theirs, except if you have a strong faith and enough Islamic knowledge to protect yourself from the disease of these people. In such a case there is no harm to learn the Qur'aan with them while taking all the necessary measures of caution from their wrong belief, and advising them and clarifying to them the truth with wisdom and good admonition. For more benefit, please refer to Fatwa: 87790.  As regards "Wahhabbism", please refer to Fatawa: 85146 and 81463.

Allaah knows best.