Are you looking for a Bi-amp package below US$1,000?
Depend on Trends TA-10.2P Class-T power amplifier! It would certainly be easier to bi-amp your speakers with two Trends TA-10.2P Class-T power amplifier (or TA-10 amplifier), connecting one of these to the highs binding posts and the other to the bass ones.
You can alternatively bi-amp your speakers using one TA 10.2P (or TA-10) per speaker. Of course each TA 10.2P (or TA-10) should be fed by a single channel only! (One TA 10.2P (or TA-10) connected to the right channel, the other to the left one). In any case, you need a signal splitter, some kind of Y or T adapter (2 pairs of RCA's outputs) to double the signal that feeds the TA 10.2P's (few $).
For example:
Trends PA-10.1D SE Tube Headphone/Pre Amplifier x 1
US$299
TA-10.2P SE Class-T Power Amplifier(with 4A Power Adaptor) x 2