ip's keep trying to log in?

Hi,
My add-on domain RussHowePTI.com is my personal training business WordPress blog and every day I get an e-mail saying lots of different IP addresses have tried logging in to the site and failed.

A friend said it was likely “robots” as they kept trying to log in using names like ‘admin’ and ‘user’ and told me to get a plugin which allowed me to block the IP addresses.

Problem is I’m getting 50+ per day and it’s too much to handle.

Is there anything I can do to stop these IP addresses from trying to log into my blog? No idea why they’re trying to do it, as my site just puts out fitness tips anyway.

I have a screenshot if it helps. Any help is greatly appreciated as Godaddy support was non-existent, seriously wish I had read reviews before I bought my hosting package from those guys.

Thanks a lot,
Russ