Problems connecting to wireless hard drive (Mac)

So, I got a new Macbook Pro (running Mountain Lion), and I have a hard drive with music files connected to my wireless router. For some reason, it takes forever to connect to/transfer files from the drive (especially importing to iTunes; it took about a week to add a measly 1,000 files). Sometimes the drive will just disconnect for no reason in the middle of transferring files. Admittedly, there’s a lot of data (about 1.1 TB of mp3s), but I’ve tried adding a few folders at a time to iTunes and it still takes forever. I didn’t have this problem at all with my old Macbook or PC laptop. Any ideas? Settings I need to change? I should also mention that I’m basically a moron when it comes to things computer-related, so if you have an answer, explain it to me as if I was a child. Thnaks!