I got a new bike computer at christmas for my road/commuter bike and chose one with cadance on. My avarage on the way to work is 70 and what i want to know is, is this about right or to low and if its to low how do i go about increasing it?

Increase it by choosing a lower gear?

It’s a bit on the low side. 90 is considered about right.
Bear in mind you said ‘average’, so if that included freewheeling, and accelerating than 70 would be good. But if you mean you’re riding along and the instantaeous reading is averaging about 70 then that’s low.
To go about speeding it up, ride in a lower gear and pedal quicker. Will probably feel odd at first.
Obviously that’s based on the assumption that you’re young and injury free.
If you’re an OAP, then don’t worry about it 🙂

It is what the computer is reading as average with a max of about 110/115 and iam only 32