First of all, your card is "powerful" enough to run that monitor. It is just old, and outdated. One of the newer features of video cards is that most of them come with a DVI connector.
The Radeon 9700 is just a hair below the top of the line conumer card, the Radeon 9800xt. I believe the 9700 sells for $200-$300 dollars. This is a powerful gamer card. If you play a lot of games, you will not be disappointed in this card. Furthermore, Radeons are known for their excellent 2d image quality as well.
If you do not play games at all, I do not think you need this type of power. You could purchase a Radeon 7000, 8500,9100, 9500, 9600, 9600xt, etc... The aforementioned cards will sell for $50-$150.
All of the Radeon series cards should have a dvi connector. Of course check the box before you purchase the item. The box will tell you that it has said connector.