@Manoj:
The position of law to your question is that the intestate property belonging to your mother will devolve on her own legal heirs consisting her children and husband. Since all of them are available, the property lying on her name (inherited from her father), can be equally shared by all the four of you.
In fact you have quoted the relevant section of the Hindu Succession Act which is very much applicable in your case, please dont have any more doubts on it and get confused. The referred provision of law is reproduced below which is applicable to your case:
(1) The property of a female Hindu dying intestate shall devolve according to the rules set out in section 16,—
(a) firstly, upon the sons and daughters (including the children of any pre-deceased son or daughter) and the husband;