Cities aren't that dark even at night, you equipment should be able to take the picture just fine.
Your first problem is that f/22 is a tiny tiny aperture, it lets very little light into the camera - so, to compensate the camera needs a very long exposure and the built in timer only goes up to 30 seconds.
I also think you might be mistaking about the meaning of the numbers you see on the camera, I don't know the D90 but most cameras, in manual mode, don't show the exposure length according to the light meter but only how many stops you are under/over (there's a scale with a little arrow, when the arrow is on 0 you are correctly exposed according to the meter).
So, start by switching the camera to A mode, set your ISO to something reasonable (don't know the D90 but try 400 or 800 as a starting point, if you get too much noise switch to a lower ISO setting) and your aperture to the lowest f number (f/3.5 if you are at 18mm, f/5.6 if you are at 55mm).
Take the picture and see 1. what shutter speed the camera's meter has chosen and 2. if you like the results, now you can switch to manual mode, the values you had in A mode and:
To make the picture darker without changing anything else use a faster shutter speed or lower the ISO.
To Make the picture brighter without changing anything else use a longer shutter speed or raise the ISO.
If you want more in focus use a smaller aperture (larger f number) and use a longer shutter speed to compensate (each click on the aperture dial is equal to a click on the shutter speed dial).
If there's too much noise lower the ISO and lower the shutter speed to compensate, if you half the ISO you need to double the shutter speed, for example if you start at 1 second at ISO 400 you can switch to 2 seconds at ISO 200
Basically:
For low light you want a small f number
Use the camera's light meter in A mode to find what the camera's think is the right exposure, start from there.
Set to brighter or darker based on your taste.
You have your aperture, shutter speed and ISO, each has side effects, you can exchange one for the other without changing the overall brightness of the photo to control those side effects (high ISO is usually noisy, lights look like starbursts in small apertures, etc.)