In this paper, we consider downward and upward vertical handovers in integrated wireless LAN and cellular networks, and address Wireless Profiled TCP premature timeouts due to steep increase of round-trip time and false fast retransmit due to packet reordering. Specifically, we develop a mobile receiver centric loosely coupled cross-layer design, which is easy to implement and deploy, backward compatible with the Wireless Application Protocol version 2 (WAP 2.0) architecture, and robust in the absence of cross-layer information. We propose two proactive schemes which prevent false fast retransmit by equalizing the round-trip delay experienced by all packets and suppress the premature timeouts by carefully inflating retransmission timeout time. We conduct extensive simulations to evaluate the performance in downward and upward vertical handovers. It is demonstrated that the proposed schemes significantly improve the performance in a wide range of network conditions.