Thanks for your prompt replies!
I have busting my brain to make it work for about 4-5 hours now, and I have kept a log of all I did
1.entered
http://monroeworld.com/android/subsonic/2.went over the "welcome", "introduction..."
3.set up server
4.installed server
5.configured server - changed port number to 8080
6.set admin password
7.configured folders
8.skipped permissions to remote folders - not needed
9.configured users
10.configured networks - "access your server over the internet" - box checked, "automatic configuration" - box unchecked, status: port forwarding disabled
11.misc configuration
12.tested the server locally - worked like a charm
13.obtained subsonic PC IP/MAC address
14.put subsonic PC on static IP - tried "Port Forward Setup Static IP address" program, status (in program: address is currently static)
15.set port forwarding - logged into router (after calling my internet provider for password and id), found "port forwarding"
-created new forwarding entry that looks like this:
service name: WWW
WAN interface: WAN1/ptm0.35
Server IP Address: 192.168.1.150 (taken from IPCONFIG /ALL under IP section)
External Port: start 8080 end 8080
Internal Port: start 8080 end 8080
Protocol: TCP/UDP
saved setting, enabled
16.testing the router - entering "http://lightmusic.subsonic.org" (set up much earlier in subsonic.org, which worked before on home wi-fi) - getting "unable to connect" from browser
-entering just "lightmusic.subsonic.org" - getting HTTP status 500 error message
17.going back to port forwarding (in case that would be the problem) - adding another forward entry with only differences being:
service name: FTP (could not give the same name as the other one)
internal port: start 80 end 80
18.testing the router - entering "http://lightmusic.subsonic.org" - getting HTTP status 500 error message
19.removing last forward entry - same result (HTTP 500 error)
20.going back to port forwarding - adding another forward entry with only differences being:
service name
and
external port: start 80 end 80
- getting message "since port 80 is used, the DSL router WEB server port in WAN side will be moved to 8080"
21.testing the router - HTTP 500 error
22.going back to setting static IP address in router menu - setting as follows:
IP address - 192.168.1.155
subnet mask - 255.255.255.0 (noted from IPCONFIG)
gateway IP address - 192.168.1.1 (also noted from IPCONFIG)
23. the internet connection drops

- IP config shows IP as before configuration of router settings with IP 192.168.1.150
24.going back to instructions (the second reply on the forum)
25.Reaching "A complete guide to setting up subsonic (win/android)"
26.downloading "simple port forwarding" program - does not have my router model in its list
27.canyouseeme.org - IP:105.102.57.10, port:8080 - "success! can see service"
28.testing in browser with IP 192.168.1.150:8080 - goes to subsonic login (as it should)
Conclusion: I have no idea what I'm doing wrong or even if I am actually doing something good (I'm new to all this)
In the end, it still works on "home" wifi (same router) from the android app and substream on iphone but only if in the server section I write "192.168.1.150:8080"
It does not work on 3g (tested on two phones using subsonic android app and substream on iphone) - in the android app I'm getting the "contacting server..." and almost immediately "a network error ocurred, retrying..." and on iphone it just loads forever
I can't test it on another network right now as I don't have access to another one (seriously considering asking the neighbors for their password

)
Whatever steps I have gotten wrong, I am willing to correct them as I've found that I developed a little obsession with making this work.
If patience with this is at hand, please indulge my lack of experience and receive plentiful thank yous
