Hi,
Are you working in a live server?
If so, please let me know your website URL and let me check. Because your 1st question doesn't make any sense to me. I should see it visually and take a look at the source codes of your website.
About the 2nd question, our VM Template doesn't come with any H1, h2, h3.... styles. So if you put something like <h1> something </h1> to long product description field. This will be styled as what ever your joomla template says. I am hopping you are talking about the long description field, because Virtuemart has 2 different product descriptions:
1 - product short description,
2 - product description (long description)
The short description is used in META tags, so it must be plain text and not longer than couple sentences. If you put some HTML tags in it, they will be removed automatically before they got saved in the DATABASE (by virtuemart, not by our VM Template). But this is not the case with long description field. You can put any HTML tags you want in it, you can even include youtube video iframe embed code if you wish. No limitation. And depends on what the CLASS and HTML TAGs are, those elements are styled with your joomla template's typography.
Regards.