Check the SN754410 datasheet. It's designed to operate with motor supply voltages of between 4.5V and 36V. What you could do is use a 4.5V or greater battery (or whatever power supply you're using, up to 36V), and then build a voltage divider on the outputs of the h-bridge to bring the voltage down to the safe operation voltage of your motors. That would only cost you a couple of resistors per output, or four resistors in total to get both directions out of one motor. You'll want resistors rated for power that can handle the maximum current from one h-bridge output, so order them from Counterparts when you order the h-bridges. Alternatively (and if you already have a lot of 1/4W resistors lying around, or you can justify buying a pack from the Source), you could run several 1/4W resistors in parallel for your voltage divider. What the heck, don't - just use one and watch ithe resistor fry! If it does, then next time use two. If they fry, next time use three. This isn't the most efficient way, but sometimes you can't beat trial and error.
You wouldn't have to do any of that if you're sending a PWM signal to the h-bridges, since you could just control the average voltage output that way, regardless of what the supply voltage is. A PWM signal on a 4.5V supply sounds like it would be the most efficient and ideal situation given the specs you claim for your motor.
The smarter alternative is to continue searching for a low voltage h-bridge IC. I'm sure there must be something like that out there. Find it (and tell me what it is!), and see if Counterparts can get it for you. Sorry, what I really should be telling you is that it might be most cost-effective to construct your own h-bridge from transistors, given your relatively low voltage and current requirement. Now that I know what kind of power you want, it's easier for me to put your original post in perspective. You were right to think you could do it with a few transistors, but the h-bridge you linked to is severe overkill for what you need. My suggestion of the SN754410 is overkill for what you need, and it's got only a fraction of the power of that beast!
I don't know if Counterparts use Paypal, but I'm guessing no since I think they do most of their business the old-fashioned way, i.e., in person. I know it's frustrating not having a credit card (I'm presuming that's why you're asking). How do I know? Because I'm 32 and I still have to borrow my girlfriend's, or mom's, or dad's! I just got turned down (again) for a credit card Friday, and here's the crazy thing: I make much more money than my girlfriend, mom, and dad! What's the lesson here, kids? Get a credit card while you're still young! I've never defaulted on a loan, or claimed bankruptcy. In fact, I'm a banker's dream: I make my payments, and I don't complain about the interest. I've paid down plenty of (student) debts, and I'm plugging away at the rest (which makes money for the banks), but the main reason I can't get a credit card? Because I never had one! They check your credit rating by, primarily, checking your history with credit cards, which after you reach a certain age becomes somewhat of a catch-22. BTW, student loans don't count - no matter how much you pay one off, in this country it doesn't mean squat to your credit rating.
Thankfully, any man and his dog can get a personal chequing account. Counterparts will probably take a personal cheque, although you might have to wait extra for them to cash the cheque. Check with them, they know better than I what they will and won't do. I still say you should look for a Counterparts equivalent in the Ottawa area, it'd save you a lot of hassle.