I'm going to show you how to take a 2D logo and make it into a 3D one using SketchUp.
Step 1: SketchUp and Plugins
If you already haven't you need to download Sketchup from http://www.sketchup.com. From there you will need to download a plugin called SketchUp STL from this site http://extensions.sketchup.com/en/content/sketchup-stl. To install this plugin launch SketchUp and open the SketchUp Preferences. In that side bar there is an Extensions option. Click on that and choose the Install Extension Button. It may ask you if you trust this plug-in. Choose yes.
Step 2: Add the Image File
Now we're going to import the 2D image file that we will base our design on. First import the full logo with ESW text and the gear symbol.
These images are available here. Use the large version for increased resolution.
Go to File > Import > and import the png files of both images, laying them out as shown in the image.
Step 3: Trace the Gear Logo
This part is really sucky, you have to trace the gear logo using the arc, line, and freeform draw tools. It's tedious, but theres no good way around it.
Protip: Use the rotate tool to avoid having to trace the whole outer gear. Also listen to this album to counteract the boredom. Or you can just use the file I uploaded to save buckets of time. Just FYI, I didn't do a very good job, but whatever.
Step 4: Add Text
Now you wanna use the 3D Text tool to create the 'ESW' part.
Use League Gothic font, check boxes for filled and extruded, and select whatever height you want the text to be.
Use the scale tool to resize the text, but make sure you don't resize in the z-direction as well.
Step 5: Add Height to the Gear Logo, Rescale, and Group the Elements
Now you have to give some height to the gear logo, by using the push/pull tool. I did this to 1 cm, which is the same height as the text.
May have to add this push/pull extensions to extrude curved surfaces.
Now group the elements and scale them to your desired scale.
Step 6: Export the .stl File
3D printers need an .stl file to print the physical object.
Step 7: Export to Your 3D Printer
I'm using a makerbot, so I used the makerware software to scale, export, the object.
If you're using the same, feel free to use my .x3g file.