Ah OK. You don't want an effect, then, you want to improve your recording quality. For acoustic guitars, the best thing you can do besides spend thousands on top quality mics and acoustically perfect room rental is to record the guitar with two mics, rather than one. This means you're going to have to up your game a bit and start working with a Digital Audio Workstation (DAW) but you really want to do that, anyway.
If you don't have two mics, don't sweat it. I'll send you a pair you can borrow and walk you through getting set up. All you'll need is the mic stands.
Then your setup will look like this
Which isn't nearly as hard as it looks.
In the mean time, do the following things.
Go here and download Reaper and install it:
It's free, and is fully functional. It will remain free, so it doesn't expire or cripple itself if you don't "buy" it later on. You can use it forever at no cost.
Once that is done, send me your Skype name. I'm off work tomorrow so I can walk you through configuring Reaper to record your Alesis interface. When you get the mics, you'll be able to plug them in and off you go.
My Skype ID is jerometoneil. Don't be afraid to chat me up (that goes for everyone ) I'll send you an email in a bit to get your address so I know where to send the mics.
Someday we'll win this thing...