I am using Psoc3 in order to implement some analog filters and other subcircuits. These filters, of course, consist of OAs and passive components such as Resistors and Capacitors. As far as I know, it is not possible to implement Resistors in PSoC Creator, am I right? And what about Capacitors? Is there any chance to implement "inside" PSoC3?
There are capacitors and resistors in PSoC3. The resistor bank available in the CT block in combination with Opamaps in the CT block is typically used to implement PGA(Programmable Gain Amplifier), TransImpedance amplifier(TIA) and similar circuits. The capacitors are typically used with the SC blocks to implement components such as Mixer. Sample Hold and so on. These can not be used as discrete capacitors.
However note that the 4 Opamaps available in PSoC3 can be used to implement filters. However please look in to the bandwidth characteristics of the Opamp if it suits your need. This can be found in PSoC3 datasheet or Opamp component datasheet.