Faster Than Cursor?

I have a cursor prcedure that is pretty slow because as the cursor moves through the data I have three select statement on the same table to find other rows information. Is there a better way to do this?

 Simple Example of Code is:

DECLARE MyVARABLES 1 to X

DECLARE c1 CURSOR

FOR

SELECT MyData1, MyData2 to X

FROM MyTable

FOR UPDATE OF MyUpdateData

--Start Cursor

OPEN c1

FETCH NEXT FROM c1

INTO MyVariables

--LOOP

WHILE @@FETCH_STATUS = 0

BEGIN

-----------------------

-- Get other rows data to add to this rows data ......GUESSING THIS IS THE SLOW PART as the table is LARGESELECT MyVar1 = MyData1

FROM MyTable

WHERE MyTableColumns = MyVariables AND MyTableColumns2 <> MyVariables2  --FINDS OTHER ROW (I have three of these)   



--Calculate & Update

If MyVarable = 'this or that'

BEGIN

UPDATE MyTable

SET MyUpdateData = MyVar1 * x *y WHERE CURRENT OF c1

END

-------------------

-- NextFETCH NEXT FROM c1

INTO MyVarables 1 to xEND

CLOSE c1

DEALLOCATE c1