Harini-if you are having doubts about the dress's modesty, ask your husband. Unless he's like mine, and thinks shorter is better.

Your husband could also ask his workmates what type of dress is appropriate for the party.
I, myself, have rarely worn anything other than sarees or fancy salwar kameez to parties since I got out of the US Army (I had to wear uniforms when I was a soldier-I do not look good in that icky Army Green). You should wear what is comfortable for you and will not make you self-conscious at the function-there is nothing worse than having to smile and act happy and friendly at a function when you are not comfortable in your outfit.
Halter neck blouse and chiffon saree is a good choice, as long as YOU are comfortable.