Dariush,
This is what I do...
1. Connection: I login with my IPAD, using my Cell Phone as a modem. On T-Mobile -- but the best idea would be to get a Wireless card from Verizon, or any other provider for your laptop.
2. The Server at the office.
If you have a dedicated IP address from your internet provider (Swbell, AT&T, whichever) then you need to set a port open for Remote Desktop connections to your Computer with Amazing charts on it.
If you do not have a dedicated IP address. Then you need to signup for a Dynamic IP address provider. I.e. DynDNS.COM (this use to be a free services, and I think it still is if you use just 1 PC). You will have to install their software on your PC at the office that you want your DR to be able to access. What is does is automatically sync a Name you pick "blah.myoffice.com" to the dynamic IP your office has. You still have to open a port to the PC on the rounter/modem in your office.
3. Once you have all that setup, then your DR can pull up REMOTE DESKTOP CONNECTION, type in the IP address to the Computer at your office, and login to the system.
-- I use my ipad to login to our office windows computer and can easily run amazing charts.
The speed will depend on your office internet connection speed. We are on a Advanced DSL, not even T1, and it's very fast. I have no speed issues, not even using my T-mobile phone as a modem for my ipad.
If you have any questions, let me know. I've been using this setup for 3 years now.