in doing job of any type, as far as computer efficiency is concened, knowledge of MS Word and MS Excel are enough. only simple formula to learn these two is to practise, practise and practise. in addtion u can refer books called Bible on MS Excel by John Wiley Publishers or MS Excel by BPB Publications, these are very good books on MS Excel. u will feel very confident after reading these books.
But do not take have diffidence that u will not get job because u are note having knowledge of computers. one can get, confidence and proficiency only after working in real environment. so confidently start searching job, if any interviewer asked for computer knowledge, tell him that I have computer knowledge. you will be able to manage the situation within one month only. This is my own true experince because I was having the same problem one year back but now i am doing my job well.
N.B. If you do not find these books them let me know, i will send u address of sites who give home delivery of books.
Good Luck