I own a domain that I purchased though Dreamhost. I do not own a hosting package. I would like to use my domain on my Tumblr blog, but my instructions form Tumblr are to change my A-Record on my domain to a specific IP address. I can not find where to do this via my panel in dream host.
You do not get DNS without a hosting package. Hosting packages include DNS services for the domain that you're hosting here.
However, I believe that there are some free DNS services out there if you Google for them.