PostgreSQL on Desktop vs. Server
Wiki answer collecting partial answers originally left in question comments

That's more than enough, you don't need a server.

60 million rows isn't that big nowadays - unless you've got huge numbers of blobs. Stick with your desktop unless you start to have major performance issues.

PostgreSQL runs better on *nix than on Windows and the number of drives is a big factor too. Nothing beats a ton of SSDs in RAID 10, but you'll be fine with your current setup!

If you want help improving your queries, you should post a question with the query and query plan from explain (analyze). See postgresql-performance for more details on which information is required for questions regarding slow queries.