Intervals are definitely the way to get faster.

However, at the point you're at, you just need to ride consistently. Try to get on the bike 5 times a week, even if its for a short time. If that's undoable, you really need to do at least 3 rides a week to see much improvement.

After you've been riding 3-5 times a week for a month, and can do an hour or two comfortably, then you want to start thinking about doing some intervals.

Right now you'll improve dramatically just by riding more often.