For filling the NaNs, you can apply this on all columns in one line as follows:
closes = resampledData['close'].fillna(method='pad')
resampledData.apply(lambda x: x.fillna(closes))
You also have a fillna
method for a DataFrame (http://pandas.pydata.org/pandas-docs/dev/generated/pandas.DataFrame.fillna.html), but this regards a Series as input as different values to use for different columns.
For the resampling, normally you can do the following to resample with different functions on multiple columns at once:
resampledData.resample('55min', how={'price':'ohlc', 'amount':'sum'})
But for me this does not seem to work with ohlc
(if you change that to eg 'mean', then it does work).