How is text converted to a number for RSA? According to http://en.wikipedia.org/wiki/RSA_%28algorithm%29#Key_generation the key length is the number of bits in n. So how can a message of many megabytes (millions of bits) be modded by a 1024 bit n? I never hear of a block mode for RSA, for instance.
You never use RSA to encrypt large binary objects, since it's to expensive to do many calculations. 

Instead, RSA is used in a key exchange or key transport protocol to send a key for a symmetric-key algorithm, such as AES (with a cipher chaining mode, such as CBC), which is then used to encrypt huge messages.

Also note that textbook RSA isn't secure. Some differences between textbook RSA and deployed RSA are mentioned there: https://crypto.stackexchange.com/a/1449/4874