Visibility problems in Router <- AP Client <-> Router configuration

Hi.

I have a problem with my pretty complicated configuration. What I want is to have second wi-fi in the other side of house with bandwidth limits on it (by second router) having Internet connection from the primary wi-fi. The primary wi-fi has been working very well separately for a while.

Tp-Link hardware list:
R1 - TD-W8960N - 192.168.1.1 - primary router connected with the Internet by ADSL connection, broadcasting wireless network, DHCP from .100 to .150
C - TL-WA501G - 192.168.2.2 - AP Client, connected to R1 with 192.168.1.199
R2 - TL-WR1043ND - 192.168.2.1 - router with a different wi-fi configured with bandwidth limits, having access to the Internet by WAN socket connected to C socket which is in AP Client mode. DHCP from .100 to .150.

Internet is working well everywhere, but I have weird problem with devices connected wireless to R1. They can't ping each other. What is more strange everything works fine after rebooting R1, but after some time (maybe after some network usage on R2) they disappear.

I'm not sure what is going on, but we cannot connect to our wireless printers on R1. It seems that computers connected with cable to R1 are always visible in this network, but I'm not sure about it.

I tried many changes on C and R2, like changing DNS servers on clients directly to R1, putting C and R2 to the same subnet as R1 with different IP ranges and with C connected to R2 by normal port, not the WAN, turning off firewall and all extra options (supporting ftp with nat etc.). Nothing helps.

It seems like some protocol is getting bad route table and devices from R1 are being visible exclusively to C or R2.

Thanks in advance for your advices what should I try.

Michal