Please Help – WordPress Beginner

Hello WordPress community, thank you for taking time to read this.
I am a 17 year old who is very good with technology, but learns from online posts. Because my poblem is a bit specific and I cannot find a direct soluion, I come to you.

I have started a business through our local CEO progam (More on that here .)

I was going through a server space you may know of – Interworx/Siteworx.
I had a mentor helping me, but I just had too many questions so I decided to take up a little side project that might end up being the acstuality of my business.

I make websites for local businesses, and I am doing this through wordpress.

Because Interworx was a little too complicated for me as I was just starting out, I decided to take an easier approach and move to awardspace. It was cheap to play around with and learn the basics of setting up a site.

NOW FOR MY QUESTION(S)
I had an old wordpress.com blog account setup and I decided to map a domain I just purchased through hover. It is being hosted through awardspace and registered with hover. My old blog (Never touched, just used it to mess with wordpress’ settings to see its capabilities.) was austinklasnerdotcom.wordpress.com

1) I have mapped the domain austinklasner.com to that very same account. It has propogated and is working. MY issue is when I type in austinklasner.com/wp-admin it brings me to austinklasnerdotcom.wordpress.com/wp-admin. I understand that this is editing the same page, but I dislike it. How can I get rid of any spec of the name austinklasnerdotcom.wordpress.com.
This is not for security purposes, just for organizational/ocd means.

2)Given all of this information, I want to know how I can go about installing plugins. I’m pretty sure I need to go into my awardspace file manager, but I do not know if that is the route I actually need to take.
I haven’t read anything other than use wordpress’ admin settings and activate it. I have the free version and want to do a workaround using my server space to install plugins without having to upgrade my wordpress, as this is only experimental.

Please help me, I have a tradeshow to attend in two days, and am having so much trouble setting this up. I still need to design at the very least a homepage by then.

Thank you, Austin Klasner.