Any drill should suffice. A battery powered drill (like mine) will only go so long before needing a recharge, therefore the more powerfull cordless drills will go longer before needing a recharge.
I just use masonry drill bits. Marco rocks is pretty light and porous, so should be easy drilling. I have light porous stuff from Vanuatu and some older more dense stuff from God knows where. The dense stuff tends to heat up and fracture, so I dont drill it any more. The lighter more porous stuff drills ridiculously easy.
Best bet is to source your acylic rod first. That's going to determine the size bit you need.
I've been able to locate both 3/8ths inch acrylic rods and 1/2 inch acrylic rods locally. The 1/2 inch hold up better, but if you use more of the 3/8ths you'll do just fine. I've got one rock that is actually 5 smaller rocks held together acrylic rods. Its now going on 7.5 years old, no issues. It used to be 6 pieces of rock, but two of the rods broke about 1.5 years ago. The rods is clear and pretty much disappears underwater.
Like I said, source your rod first, determine the diameter, and then buy your drill bits. Most drills common homeowner drills have a 3/8ths inch chuck, meaning they can only handle bits up to 3/8ths inch. However, professional series drills can have a 1/2 inch chuck, so possible rental is one way to go. Also, bits are made up to 1/2 inch in diameter at the bit with a 3/8ths inch base to fit into smaller drills, however, these can be tougher to find, so look around. You're going to want both 12 and 18 inch long bits.
I would start off test drilling on some smaller pieces you wont be using for practice.
Also, you can use a mitre saw to cut the rock as well, if its porous and light. Heavier, more dense rock is going to need a tile saw.
Fun times ahead...