How I can?

How can I get around the fact that raids like Naxxramas/Ulduar or other raids from older patches never start? I'm full purple (epic loot dungeon) but I don't have the GS to do TOC or ICC.

Farm some money to buy BoEs from Aauction house, that should give you solid enough gear to do toc 25 and ICC 10 mans, even 25 on some alt runs on the last day before reset. Also you can use vote points to buy some of the Ulduar trinkets, depending on your class and spec

Vote points from daily log in can get you 239 Ulduar HM gear. Can get you into some TOC pugs. Takes a while to build up. Farm emblems daily. Do the weekly raid quest for 5 EOF/EOT's. First character made takes a while to gear up. Professions if you have crafting professions. Farm materials for craftable gear.

Naxx and Ulduar are easily skipped thanks to ToC and Frozen Halls dungeons: Forge of Souls, Pit of Saron, and Halls of Reflection.

Naxx drops ilvl 200/213 items, KT dropping 213/226.
Ulduar drops ilvl 219/226 items, Yogg-Saron dropping 219/226, hardmode drops are 232/239.

ToC5 drops ilvl 200/219 items.
Frozen Halls dungeons drops ilvl 219-232 items.
Emblems of Triumph are used to buy ilvl 232/245 items.

Once you've spammed enough RDF HC to get FoS HC pop up for you, you do it only for daily EoF, and EoT if you wish to.
Otherwise spamming ToC/Frozen Halls dungeons will get you EoT as well, and the gear that may drop for you there. I recommend focusing on Frozen Halls dungeons. Doing those will out-gear Naxx/Ulduar items in a week. You can spam ToC/FH dungeons, unlike Naxx/Ulduar that are limited to two runs a week (10 & 25) each. Naxx/Ulduar naturally takes more effort to run and organize than some dungeons that can be spammed.

AH may have ilvl 200-264 BoE items that can help with gearing up. Gather activity points as you play for up to 239 ilvl items. Spend them wisely, and make sure you buy them on the right character.