I'm a support rogue as well, but I'd like to chime in. Currently your ammy is fine, while most opt for runic, I think the extra stat points and attack on trailblazer make it a better option. As Lord suggested, a skain/gara attack misc will help a lot, but there are decent alternatives like the 2016 ostara assassinate charm (While it isn't great, even royal adds decent attack). Proteus attack braces are a good choice, but you've already stated you're going to buy some, so I'm just being redundant. If you lix at every kill I'd say runic valour (or dagger) x3 with divine ring, otherwise what Lord suggested is better. DL/EDL weapons are nice to have, but a necro or 200 shop dagger and spite work well until then. As Corrupt stated earlier, try to get an attack mord helm, it definitely helps a lot.
7k hp
500-750 dex
rest in str
(add focus if you need it)
50/45 sneaky
50/45 quick
45/45 shadow
42/45 double
45/45 rend (or poison weapons if you prefer, but in high str builds I'd go with rend)
I haven't been dps build since 219, so I might be a bit rusty, but I believe this works well enough.
Reaper adds more attack than dagger and gives a nice skill