If you need to use the files from these MS Office programs, then a good choice would be to purchase the iWork SuiteLOOK HERE - this suite includes Numbers (mimics Excel), Pages (Word), & Keynote (PowerPoint) - these programs can read files from the MS ones (along w/ other options) - they are not as powerful as the MS suite, but worth exploring; each is only about $10.
There are some other choices and others will likely 'chime in' - good luck!
There is no way to get MS Office to work natively on the iPad. You can either use one of the iPad office suites, or use a remote desktop program like SplashTop to control a pc and use MS Office that way.