Your videocard already has VGA output, or it should (I've yet to see a PC videocard that has only DVI-D ports on it).
The DVI ports on your card are DVI-I and should have the "four plus crosskey" section on the one side of the connector. That section is the analog (VGA) section. All you need to get VGA output from the card is a simple, widely/cheaply available, DVI-VGA adapter to use the VGA signals in that portion of the connector.
At least one of these adapters are usually packaged with videocards, so you may not even have to buy one, just check your videocard box, if you still have it (or if you ever had a box for it).

The DVI ports on your card are DVI-I and should have the "four plus crosskey" section on the one side of the connector. That section is the analog (VGA) section. All you need to get VGA output from the card is a simple, widely/cheaply available, DVI-VGA adapter to use the VGA signals in that portion of the connector.
At least one of these adapters are usually packaged with videocards, so you may not even have to buy one, just check your videocard box, if you still have it (or if you ever had a box for it).