Did you solve your problems? If not I recommend to read
- How to power: As mentioned on that page for power you might go for a NiMH (or LiPo pack) as used for RC cars. They can deliver the current needed for the high torque (... the H bridges you use are specified for 0,6 A which according to your post worked ...). There will be a tradeoff between voltage, capacity (how long does it work before recharging is required) on one and size, weight on the other side. And of course: The more capacity the higher the hazard in case of a shortcut.
- How to connect the IR remote as pins are taken ...
That depends on availability of pins of the Arduino (which?) and the libraries you are using. As I understood your post, you had already something working. Could you provide your code for a view? Usually to recieve IR signals only one digital input is required. Depending on the Lib you may redefine the pin used in your sketch either as a #define or in the initialisation of the receiver object. - L2930 as an alternative: I recommend to stick with the shield unless you or someone else knows an appropriate library to drive the chip. The control of servos follows a certain timing...
I cannot promise that my support will be sufficient and lead to a success, but let's give it a reasonable try ... if you are still interested 