According to Muslim law, marriages are of three kinds: (i) sahih or valid; (ii) batil or void; and (iii) fasil or irregular. The Muslim law, does not classify any marriage as voidable marriage. A sahih or valid marriage is one that is contracted by observing all the conditions of marriage. If some of those conditions are violated, the marriage is batil or void. Those conditions are: consanguinity, affinity, forterage, marriage by a Muslim woman without divorce by a living husband. If some other conditions are violated the marriage is declared fasil or irregular.
Irregular (fasil) marriages are: (i) marriage contracted without witnesses; (ii) marriage with a fifth wife when four wives are present; (iii) marriage during the iddat period; (iv) marriage prohibited on the grounds of a different religion; (v) marriage prohibited as an unlawful conjunction.
Therefore there is no ground or reason for declaring your marriage as void under the said grounds in your case.
A Muslim marriage can be dissolved by divorce by the parties without recourse to the court and on certain grounds by recourse to the court.
The law as ordained by the Holy Quran is that talaq must be for a reasonable cause and that it must be preceded by an attempt at reconciliation between the husband and the wife by two arbiters, one chosen by the wife from her family and the other by the husband from his family. If their attempts fail then talaq may be effective.
Thus talaq is the only relief available to you. If your marriage with her has to be dissolved through talaq then the other formalities in this regard have to be strictly followed. So think of the mehr or dower amount to be given for pronouncing talaq.