access my computer throuht router

Well, generally, you can use GotoMyPC, or Symantec's PCAnywhere. If both of the PC's you will be using are running XP, then you can also use RemoteDesktop.
Since I have not personally used the first two above, I will concentrate on RDC. To use, you need to have a static IP address configured on the PC you want to connect to. Your router will have to be able to forward RDP sessions to the IP address you setup. Use port-forwarding options in your router setup, and enable port 3389 to be forwarded to your static IP address.
You also need to know the public IP address of your router, which is not always easy if your ISP assigns dynamic IP addresses.
To make this easier, I use FollowMEIP from fmip.org. After setting up a free account, you can download and setup to upload your current IP address to their server. You can access by logging in and viewing your recent IP addresses obtained by your home PC. ( you need the info to connect using Remote Desktop.)

What's your OS? If it's XP,you can allow remote management. Right-click on "My Computer" go to the Remote Management tab and check Remote Assistance. Afterwards, configure your router to (via the Application page) allow port 3389 to pass your router and send it to the IP address of the machine you want to remotely access.

Windows 2000 Server requires you to install the terminal server option onto your computer.

Understand there are security risks associated with this concept. You should give yourself a STRONG password and a unique userid (do not use administrator). Hope this helps.