The only other thing that might work is the smallest size flat screwdriver from a mini-screwdriver set similar to this:
If you have one like this that fits into one of the three "wings" in the screw head, you could try very carefully rotating the screwdriver to unscrew the four tri-wing screws that you need to remove to get into the DS Lite. Be very careful if you decide to try this though, if you strip the screws then you'll have no way of getting in whatsoever.
I'm assuming the reason you can't order online is you don't have a credit card? If so you could try setting up PayPal to use your bank account, if that's not an option then it may be worthwhile asking a friend or family member with a credit card to order the triwing screwdriver from DX for you, it's only $0.85 (free shipping) so I'm sure you could convince someone to order it for you if you give them $1 cash.