Two databases, one install

Noob question …

I have the following setup currently …

? a paid unlimited hosting account
? a domain
? my original personal site at the top level of my /public_html/, incorporating a self-hosted podcast, using the domain
? an existing WP installation for a basic blog, installed in a directory under /public-html/, using a path based subdomain (my.domain/blog)

What I now want to finish up with is a single WP installing incorporating both the blog and the podcast, each with a path based subdomain (as well as other individual pages). I anticipate installation a plugin such as podpress to host the podcast.

To achieve this as simply and functionally as possible, do I want to convert my existing WP installation to a multisite network? Or is there a better / simpler way of producing my desired result?

Thanks.