ADSL 2+ Bridge Modem Help

Any tech savy on OzBargain? Need help with modem/adsl problem.
Current setup:
Modem: TP Link TD-8817 (bridgemode) (192.168.0.1)
Router: Asus rt-ac68U (latest merlin August firmware) (192.168.1.1)

Sight of line:

You are 1607 m from PEND as the crow flies.
Estimated cable length of 2330.15 m.
Estimated speed of 11666
Zone 1

Device Information

Firmware Version : 8.0.0 Build 140311 Rel.29246
ADSL Firmware Version : FwVer:3.22.2.0_A60394 HwVer:T14.F7_12.0
Line State : Showtime
Modulation:ADSL2 PLUS
Annex Mode:ANNEX_A
Downstream | Upstream
SNR Margin:10.5 | 15.7 db
Line Attenuation:38.7 | 21.9 db
Data Rate:7547 | 812 kbps
Max Rate:7936 | 944 kbps
POWER:0.0 | 12.5 dbm
CRC:7086 | 65503

Connection keeps dropping out more often. Here is extract from router:

ep 3 00:36:35 pppd[588]: Connection terminated.
Sep 3 00:36:36 pppd[588]: Sent PADT
Sep 3 00:36:36 pppd[588]: Modem hangup
Sep 3 00:37:21 pppd[588]: Timeout waiting for PADO packets
Sep 3 00:37:21 pppd[588]: PPP session is 354 (0x162)
Sep 3 00:37:21 pppd[588]: Connected to 00:30:88:1b:9d:cf via interface eth0
Sep 3 00:37:21 pppd[588]: Using interface ppp0
Sep 3 00:37:21 pppd[588]: Connect: ppp0 <—> eth0
Sep 3 00:37:21 pppd[588]: PAP authentication succeeded

Here is another extract of stat somewhere below other stats:

Sep 3 00:37:23 WAN_Connection: WAN was restored.
Sep 3 00:37:23 rc_service: ip-up 17676:notify_rc start_upnp
Sep 3 00:37:23 rc_service: waitting "stop_upnp" via ip-up …
Sep 3 00:37:23 miniupnpd[17717]: shutting down MiniUPnPd
Sep 3 00:37:25 miniupnpd[17721]: HTTP listening on port [55XXX]
Sep 3 00:37:25 miniupnpd[17721]: Listening for NAT-PMP/PCP traffic on port 5351
Sep 3 00:37:31 rc_service: ip-up 17676:notify_rc start_firewall
Sep 3 00:37:32 dnsmasq-dhcp[477]: DHCPREQUEST(br0) [Censored]
Sep 3 00:37:32 dnsmasq-dhcp[477]: DHCPACK(br0) [Censored]
Sep 3 00:37:33 miniupnpd[17721]: shutting down MiniUPnPd
Sep 3 00:37:33 start_nat_rules: apply the nat_rules(/tmp/nat_rules_ppp0_eth0)!
Sep 3 00:37:34 miniupnpd[18005]: HTTP listening on port [55XXX]
Sep 3 00:37:34 miniupnpd[18005]: Listening for NAT-PMP/PCP traffic on port [5XXX]

Can someone help me to the right direction. Adsl 2+ from optus is crap atm. Finally found used modem (TP LINK 8817) which seems to keep dropping internet connection. What could be the cause and what is the best modem for situtation.

Any help will be greatly appreciated. Thanks in advance.