How fast can I expect blood to be re-absorbed after an internal eye hemorrhage?

Days to months. If it's a vitreous hemorrhage, it can take a long time to reabsorb depending on the amount. Sometimes if non-clearing and visually significant, the blood is removed through vitrectomy surgery.
Depends. A lot depends on the origin of the blood - trauma, retinal neovascularization, diabetes - and the amount of blood. Usually significant clearing can be seen in 2-3 weeks but sometime surgery is necessary (vitrectomy) to clear the blood and determine the underlying problem.