Replaced hard drive - trying to do a clean install of OS-X on 2011 Macbook Pro
Well if you have no other Mac, nor access to another Mac that you can download Mavericks with then you'll have to use internet recovery.

Boot the Mac holding down COMMAND-R (on a PC keyboard that would be WINDOWS-R) And if there is no recovery partition you go into internet recovery and get the OS your Mac shipped with (Possibly Mountain Lion).

Probably best to use a wired connection otherwise it will take hours.

I gather it's not difficult to do, but Apple has a knowledge base article here with the details.

http://support.apple.com/kb/HT4718?viewlocale=en_US&amp;locale=en_US

Once you get Mountain Lion installed you can use the App Store to download Mavericks. 

And if you just have to start with Mavericks, you'll have to find a friend with a Mac that can download that installer for you...