Flexible two-column posts

Hi everybody,

So I’m trying to set up my blog so I can write posts in two columns. The idea is to put the post in english in one column and in spanish or dutch in the other. So far what I was doing was using a small piece of code directly in the post

<div style="float: left; width: 48%;">
</div>
<div style="float: right; width: 48%;">
</div>

https://wordsandotherbodyparts.wordpress.com/2013/02/09/lorem-ipsum/

This looked easy enough and apparently worked. The problem appears when I try to put images in one of the columns and not the other. Doing that things like this happen:

https://wordsandotherbodyparts.wordpress.com/2013/03/11/the-proof/

The thing is: I don’t want to set up my blog to write always in two columns. I want to be able to put images in one of the columns or in both or above both columns as a header inside the post, etc. I also want to be able to post without using the columns.

Do you think there’s any way to do this?

I purchased the custom design but I have very little idea of css.
Ah, I use a mac, and so far I haven’t been able to find an editor for wordpress.

Thank you very much for your help ??