Write some software -- 2

We would like a get a minor configuration on asterisk. We have already created extensions and we are looking for two more features. When we call a conference number from our softphone other softphones should need to automatically get into the conference room. Another one, we can able to call locally with LAN but we are unable to call via Internet. We are in bit urgency. Can you please let us know how long will it take to complete. We are using linux platform. Thanks.