A simple solution would be Gnome-Tweak-Tool, also known in the software center as "Advanced Settings". Now you may use this to change the font size affecting the software center, however unfortunately all other applications as well. A recommended way to preform the font change would be to open the settings, change the font size, and then when done with the software center, return it to it's original form, or however you prefer it. If you can't get the application from the software center, due to the small size of the font just paste the following into your terminal -
sudo apt-get update
sudo apt-get install gnome-tweak-tool
Here is what Advanced Settings should appear as, simply click the font size next to the default font to make changes.
Well, you don't really want to mess with the other settings I'm assuming, (Graphics Drivers, or Screen Resolution) But, just to voice other solutions, you could start by seeing if this is the graphics driver, I personally use the open source one because I have no other choice than binary blobs, or the screen resolution could be toned down to make the text appear larger... I hope any of this can help!