In heterogeneous mobile adhoc networks, nodes are likely to transmit at different power levels, thereby resulting communication links of varying range. Traditional MAC protocols that implicitly assume that links are bi-directional and uniform energy distribution will either fail or perform badly. As well Interference and signal loss due to distance and fading severely diminish the total throughput attained in heterogeneous networks. We propose a new protocol based upon the existing IEEE802.11, which adaptively transmits the data frames through energy efficient nodes or through a list of high data rate assistant nodes. We show by simulation that our protocol significantly reduces the energy and delay and achieves high throughput, when compared with the Hybrid MAC (HMAC) and traditional 802.11 protocols.