Read from file strings

Question

have next file:

Debit
100
12.03.2011
200
13.01.2011
300
09.05.2011

Credit
70
12.01.2011
40
09.05.2011


To display information as follows:

Debit:
<amount 1> from <date1>
.................................
<amount n> from <daten>

Credit:
<amount 1> from <date1>
..................................
<amount n> from <daten>

Balance: totat debit-total credit

I undestand logically thow do in, but how technical, cant. Please,  help me