How to use 2 monitors with one port?

[Gryff99]

I have a DVI and a VGA monitor. My DVI monitor is the only one that fits in the back of my card (GeForce GTX 970), which is good, seeing as it's my main one. However, I want to know how to set my second monitor to use my onboard card, so I can use it again. Any help is appreciated.

 

[Luminary]

Best way I can think of is getting two proper adapters for each port:

1) A DVI-I to VGA adapter for your older monitor (Example)
2) A HDMI to DVI adapter for your newer monitor (Example)

DVI-I also carries an analog signal which is why an adapter from DVI-I to VGA would be a perfectly good solution. That way both monitors are hooked up to the GTX 970.