Im really looking for some sage advice from people already in the database field.

I have a degree in Internet Technology where i have done plenty on designing databases, normalisation, sql, a few programming/scripting languages and plenty of Linux stuff.
The problem is with all this fantastic knowledge i have no experience so im stuck working in a Telecom companies billing department using my sql skills to produce itemisation that generally consists of
Code:
select * from call_detail where cust_id ='****' and invoice_date = '2007-11-13'
So what i would like to know is what sort of course you would recommend to me to get into this field? Is it worth spending the money to become oracle certified?
and if so what sort of level would i be able to get a job in this field to help pay for further studies?

what else can i do from home to help myself ?
what books does everyone recommend to read ? anything Lamp related would be ideal really, i do have spare machines laying about so im willing to try out any software that would be of use.

sorry for the mass of questions but any replies would be greatly appreciated.