How can I repair the agitator on my hotpoint washer?
I found this doing a web search and think it will be helpful:

“5-5 AGITATOR
Most GE-designed washing machine agitators are not fastened to the shaft by any screws or bolts. To remove, simply tug upwards on the bottom of the agitator. There are exceptions; see "handwash" agitators below. 

If you find that you cannot remove the agitator by pulling on it, try tapping the top of the agitator gently with a rubber or wooden mallet. If you still cannot remove the agitator, pry off the plastic cap in the center. Then cut out the little piece of plastic in the center of the hub with a knife; this will expose the top of the agitator shaft. (Figure GE-6)Hit it with a little WD-40 to loosen it. 

GE-designed agitators have a removable rubber spline insert that connects the agitator to the transmission shaft splines (Figure GE-6.) If the splines are stripped, you can replace the whole agitator, or just the rubber spline insert. 

Figure GE-6: Agitator Hub



To remove the insert, remove the plastic cap and cut out the center plastic piece as described above. Push out the old spline insert (it can be difficult.) To replace, put the new insert onto the top of the transmission shaft and push the agitator down onto it. 

Hotpoint and JC Penney have a "handwash" agitator on some designs. The "handwash" agitator is actually a small agitator that fits inside the larger, main agitator.
The "handwash" agitator has a small screw underneath the metal disc on top of the agitator; make sure you remove it before trying to pull up on the "handwash" agitator. There are locking tabs that you must twist to remove the larger agitator from the smaller one. 

Once the screw is removed, the "handwash" agitator should lift out easily. If not, tap with a rubber mallet a described above, or shoot some WD-40 into the screw hole.”

Source: http://www.appliancerepair.net/washing-machine-repair-5.html