First off, I have to wonder about the accuracy of your pH meter. Soils of pH 3 do exist in the world, but are quite rare -- that's exceedingly acidic. And in a dry climate like Kuwait, I'd be very surprised indeed. Now, if this is an artificial potting mix, maybe, but even there, 3.0 is amazingly acidic. Was your meter calibrated with standard buffers?
In any case, assuming your pH is too low, you can use calcium carbonate (also known as calcic lime, limestone, agricultural lime, Hi-Cal) or dolomitic limestone (a natural mixture of calcium carbonate and magnesium carbonate, also known as dolomite, dolostone). While both are generally considered slow-acting, assuming your soil really is that acidic, they'll work fairly quickly. They should be well-incorporated into the soil, since surface applications are not very effective. Also, the smaller the particle size is, the faster they act, so a powdery form will better than a gritty, sandy form of the material.
You could also use calcium oxide (burned lime, quicklime), or calcium hydroxide (slaked lime, hydrated lime), and since both are highly water-soluble, they will move into the root zone and raise the pH almost instantaneously. But if you go that route, realize that both of those materials are highly caustic and dangerous to handle, and if you use too much, they can raise the soil pH far higher than you want, almost immediately. One advantage of the limestone or dolomite is that the closer the pH gets to 7, the slower they continue to act. So it's much less likely that you'll overdose your soil.
