If you're Internet connection is faulty then tell your ISP - I've often found that they can magically fix faults if only they know about them.
If it's always going to be this slow, though, I'd think about buying a CD. The link's easy to find on Mint's homepage, under downloads, option to the right.
Finally, depending on where you are, you might be able to get in touch with a local Linux User Group or the equivalent where you live. There'll be someone there who can obtain and burn a Mint or other distro disc for you.