Welcome to FlyerTalk, bananapointjunkie!

Yes, there are many ways to buy points. So far as I know, every airline allows you to buy miles; just check their website. Amex MR points can be transferred to a few airlines. You can just transfer to the airline you want, and then buy miles to "top off" your account.

But make sure you actually need to. For example, you can transfer your American Express Membership Rewards points to Delta, often with a 50% bonus. So if you had, say, 100,000 MR points, you could transfer to Delta for 150k points, which should be more than enough for a business class ticket to wherever you want to go. This is typically a "limited time" promotion, but it rolls around every couple of months. So if you don't need miles immediately, consider waiting fora Delta promotion.