Since you have a background in economics you may go for business intelligence or financial software. For BI you need knowledge of databases (SQL, stored procedures, data warehousing), Java EE, familiarity with BI suites (Oracle, SAP). For financial software it's a long term commitment, you need to master advanced data structures and algorithms (tree, graphs, networks, linear programming, dynamic programming, numeric methods), some AI topics (data mining, machine learning), statistical modelling (the math behind it, R language), low level programming (C/C++, memory management, multithreading, interprocess communication). The reward is proportional to the effort (higher entry barrier means bigger gain), so you can do CMS tweakings for lower and fragmented returns, or work on more serious systems for higher paychecks and job security.