a pair of these should give you a decent amount of light, if you prefer 23w, you can shop around, but for $10, if you don't use them in your viv, you can use them around the house.
EnergySaver 13-Watt (60-Watt) T2 Compact Fluorescent Daylight (6500K) Light Bulb (4-Pack) (E)*-420091 at The Home Depot