Requirements specification of FMCG company

I m the manager of a small FMCG company that manufactures Shampoo.Our company is expanding very rapidly and we are able to cover the entire state of West Bengal this year.To make our business more efficient we want an order management system.The salespersons of our company go around the state taking orders.There is a central depot in Kolkata.The orders taken from different parts of the state are dispatched from the central depot.The order management system needs to satisfy the following requirements:-
1)Our company manufactures four kinds of shampoos namely Anti-dandruff shampoo,Herbal shampoo,silky hair shampoo and Anti-hairfall shampoo.
2)All the shampoos are available in three sizes i.e 50ml,100ml and 150ml.
3)The order management system should perform the following function on receiving a request
a)It should ask for the type/types of shampoos ordered and the size of each type of shampoo.e.g 100 pieces of Anti-dandruff shampoo of size 50ml,20 pieces of silky hair of 100ml etc.
b)It should check if the quantity of stock is greater than or equal to the quantity ordered in each category.
c)If the quantity of stock is greater than or equal to the quantity ordered for a particular item than record the order,send an order accepted message to the salesman and reduce the stock by the ordered quantity.
d)If the quantity of stock is less than the quantity ordered for a particular item than reject the order and send an "out-of-stock" message to the sales man.
e)Thus a salesman can get his/her total order accepted or a part of his/her order accepted by the system depending upon the stocks available.
f)No two salespersons can access the order management system at the same time and each salesperson should get the updated stock level every time he/she uses the system.
4)The order management should have an authentication check in the beginning i.e it should ask for a password so that only genuine persons access the system.
5)The order management system should have a good user interface and should be compatible to both personal computers and mobile phones.
6)The order management system should be easy to maintain.
7)It should be easy to install.
I now invite quotation for this software project.Any company with good service record can send their quotations before 1st December,2008.
With regards
Govind prasad sahu.