How do I get awk to ignore letters/punctuation?

[Torricelli]

Hello everyone. As my first post here, I have a question about the command "awk".

The situation is as follows: I did a minimal install of Debian on my laptop a couple of days ago, and decided to use wmii as my window manager.
After installing necessary packages and tweaking some stuff, I started editing my wmiirc, and changed the colors, added some shortcuts and added stuff to the notification area (I'm just going to assume it's called the notification area), and used Google to find out how to add battery info and wireless strength.
Now, the problem is, it shows a small period after the strength, and I want it gone.

Here's also a picture of my notification area:
notification area.jpg

And here's the line for the wireless strength in my wmiirc:

'Signal strength:' $(awk '/wlan0:/ {print $3}' /proc/net/wireless)'/70'

So, is there any way to ignore letters or punctuation?

Thanks in advance.