Q: How do I increase my speed?

What all 3rd party extentions are you running?

EtreCheck is a simple little app to display the important details of your system configuration and allow you to copy that information to the Clipboard. It is meant to be used with Apple Support Communities to help people help you with your Mac.

http://www.etresoft.com/etrecheck

Easiest way is to add memory.

http://www.datamemorysystems.com/apple-imac-intel-core-i5-quad-core-2-8ghz-27-mc 511ll/a-mid-2010-memory-upgrades/

There are other things, change the hard drive to an SSD, or possible processor upgrade, but that would require disassembly...

Memory is easy, remove a door/panel, pop in two chips.

I would add two 8 gig modules, third one from the bottom on the page I linked....

This would give you 20 gigs memory total...