Check out this MAX280. Its a 5th order Low Pass Filter IC:
http://datasheets.maxim-ic.com/en/ds/MAX280-MXL1062.pdf
That in combination with an op amp for gain should make your life easier.
Look at Figure 6 on Page 7. that should be exactly what you need. It eliminates the need for multiple caps and resistors if you want a higher order filter, which you might need, depending on the results you get.